The CARD11-BCL10-MALT1 (CBM ) signalosome complex:Stepping into the limelight of human primaryimmunodeficiency

Stuart E. Turvey, MBBS, DPhil, FRCPC,a Anne Durandy, MD, PhD,b Alain Fischer, MD, PhD,b,c Shan-Yu Fung, PhD,a

Raif S. Geha, MD,d Andreas Gewies, PhD,e Thomas Giese, MD,f Johann Greil, MD,g B€arbel Keller, MSc,h

Margaret L. McKinnon, MD,i B�en�edicte Neven, MD,c Jacob Rozmus, MD,a J€urgen Ruland, MD,j Andrew L. Snow, PhD,k

Polina Stepensky, MD,l and Klaus Warnatz, MDh Vancouver, British Columbia, Canada, Paris, France, Boston, Mass,

Heidelberg, Freiburg, and Munich, Germany, Bethesda, Md, and Jerusalem, Israel

Next-generation DNA sequencing has accelerated the geneticcharacterization of many human primary immunodeficiencydiseases (PIDs). These discoveries can be lifesaving for theaffected patients and also provide a unique opportunity tostudy the effect of specific genes on human immune function.In the past 18 months, a number of independent groups havebegun to define novel PIDs caused by defects in the caspaserecruitment domain family, member 11 (CARD11)–B-cellchronic lymphocytic leukemia/lymphoma 10 (BCL10)–mucosa-associated lymphoid tissue lymphoma translocationgene 1 (MALT1 [CBM]) signalosome complex. The CBMcomplex forms an essential molecular link between thetriggering of cell-surface antigen receptors and nuclearfactor kB activation. Germline mutations affecting the CBMcomplex are now recognized as the cause of novel combinedimmunodeficiency phenotypes, which all share abnormalnuclear factor kB activation and dysregulated B-celldevelopment as defining features. For this ‘‘Currentperspectives’’ article, we have engaged experts in both basicbiology and clinical immunology to capture the worldwideexperience in recognizing and managing patients with PIDscaused by CBM complex mutations. (J Allergy ClinImmunol 2014;134:276-84.)

From athe Department of Pediatrics, Child & Family Research Institute, and BC Chil-

dren’s Hospital, University of British Columbia, Vancouver; bthe National Institute

of Health andMedical Research and the Department of Immunology and Hematology,

Assistance Publique-Hopitaux de Paris, Necker Children’s Hospital, Paris, and

Descartes-Sorbonne Paris Cit�e University of Paris, Imagine Institute, Paris; cUnit�e

d’immuno-h�ematologie p�ediatrique, Hopital Necker-Enfant Malades, Assistance

Publique des Hopitaux de Paris (APHP), Paris; dthe Division of Immunology, Boston

Children’s Hospital and Department of Pediatrics, Harvard Medical School, Boston;eGerman Cancer Consortium (DKTK), partner site Munich at the Institut f€ur Klinische

Chemie und Pathobiochemie, Klinikum rechts der Isar, Technische Universit€at

M€unchen, Munich, and German Cancer Research Center (DKFZ), Heidelberg; fthe

Institute for Immunology and gthe Department of Pediatric Oncology, Hematology

and Immunology, University of Heidelberg; hthe Centre for Chronic Immunodefi-

ciency (CCI), University Medical Center Freiburg and University of Freiburg; ithe

Department of Medical Genetics, Child & Family Research Institute and BC Chil-

dren’s Hospital, University of British Columbia, Vancouver; jInstitut f€ur Klinische

Chemie und Pathobiochemie, Klinikum rechts der Isar, Technische Universit€at

M€unchen,Munich; kthe Department of Pharmacology, Uniformed Services University

of the Health Sciences, Bethesda; and lPediatric Hematology-Oncology and Bone

Marrow Transplantation, Hadassah Hebrew University Medical Center, Jerusalem.

S.E.T. holds the Aubrey J. Tingle Professorship in Pediatric Immunology and is a clinical

scholar of the Michael Smith Foundation for Health Research. J.R. is a Vanier Canada

Graduate Scholar. Supported in part by funding from the Canadian Institutes of Health

Research (MOP133691 to S.E.T.); the National Institutes of Health (AI100315 and

AI094017) and a Dubai-Harvard Foundation of Medical Research grant (both to

R.S.G.); DZIF (German Center for Infection Research) and the European

Research Council under the European Union’s Seventh Framework Programme

276

Key words: CARD11-BCL10-MALT1 signalosome complex,primary immunodeficiency diseases, combined immunodeficiency,congenital B-cell lymphocytosis, paracaspase, next-generationsequencing, nuclear factor kB, CARMA1

Primary immunodeficiency diseases (PIDs) are a group of heri-table genetic disorders in which parts of the human immune systemaremissingordysfunctional.1 PIDs interferewith essential protectiveimmune functions, greatly enhancing susceptibility to infections,autoimmunity, inflammatory organ damage, and malignancy.

PIDs, often referred to as ‘‘experiments of nature,’’ have had acritical role in expanding our understanding of the immune systemand in the development of new treatments that have applicationsfar beyond immunodeficiency diseases. Key discoveries infundamental biology have also emerged from the identificationof PID-causing genes. Examples of these transformative disco-veries arising from the study of rare PIDs include immunedysregulation–polyendocrinopathy–enteropathy–X-linked syn-drome caused by mutations in the forkhead box protein 3gene (FOXP3),2,3 severe autoimmunity caused by mutations inthe tolerance regulator gene autoimmune regulator (AIRE),4,5

and severe combined immunodeficiency (SCID) caused by

(FP7/2007-2013)/European Research Council grant agreement no. 322865 (to J.R.);

a Concern Foundation Conquer Cancer Now Award (to A.L.S.); and the Federal

Ministry of Education and Research (BMBF 01 EO1303 to K.W.).

Disclosure of potential conflict of interest: S. E. Turvey’s institution has received funding

from the Canadian Institutes of Health Research. A. Durandy’s institution has received

a grant from the European Research Council, as has that of A. Fischer and that of A.

Gewies, whose institution has also received funding from the German Research Foun-

dation (DFG), and the Helmholtz Association. T. Giese is employed at the University

Hospital HD and has received consultancy fees from Search-LC. J. Ruland’s institution

has also received grants from the European Research Council, the DFG, and the Helm-

holtz Foundation. A. L. Snow’s institution has received funding from the Concern

Foundation for Cancer Research. K.Warnatz has received compensation for delivering

lectures from Baxter, GlaxoSmithKline, CSL Behring, Pfizer, the AAAAI, Biotest,

Novartis Pharma, Stallergenes AG, Roche, Meridian HealthComms, and Octapharma

and has received compensation for manuscript preparation from UCB Pharma; his

institution has received payment for the development of educational presentations

from the European Society for Immunodeficiencies. The rest of the authors declare

that they have no relevant conflicts of interest.

Received for publication April 23, 2014; revised June 7, 2014; accepted for publication

June 10, 2014.

Corresponding author: Stuart E. Turvey, MBBS, DPhil, FRCPC, Child & Family

Research Institute, 950West 28 Ave, Vancouver, British Columbia V5Z 4H4, Canada.

E-mail: sturvey@cw.bc.ca.

0091-6749/$36.00

� 2014 American Academy of Allergy, Asthma & Immunology

http://dx.doi.org/10.1016/j.jaci.2014.06.015

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Abbreviations used

AgR: A

ntigen receptor

Akt: S

erine/threonine-specific protein kinase also

known as protein kinase B

B-CLL: B

-cell chronic lymphocytic leukemia

BCL10: B

-cell chronic lymphocytic leukemia/

lymphoma 10

BCR: B

-cell receptor

BENTA: B

-cell expansion with NF-kB and T-cell anergy

BLNK: B

-cell linker

BTK: B

ruton agammaglobulinema tyrosine kinase

CARD11: C

aspase recruitment domain family, member 11

CARMA1: C

ARD-containing MAGUK protein 1

CBM: C

ARD11-BCL10-MALT1

CC: C

oiled-coil

CID: C

ombined immunodeficiency disorder

CK1a: C

asein kinase 1 alpha

DAG: D

iacylglycerol

DLBCL: D

iffuse large B-cell lymphoma

HSV: H

erpes simplex virus

IAP2: I

nhibitor of apoptosis 2

IgH: I

mmunoglobulin heavy locus

IkBa: N

uclear factor of k light polypeptide gene

enhancer in B-cell inhibitor a

IKK: I

nhibitor of kB kinase

IP3: I

nositol-1, 4, 5-triphosphate

ITAMs: I

mmunoreceptor tyrosine-based activation

motifs

ITK: I

L2-inducible T-cell kinase

JNK: c

-Jun N-terminal kinase

LAT: L

inker for activation of T-cells

MAGUK: M

embrane-associated guanylate-kinase

MALT lymphomas: M

ucosa-associated lymphoid tissue lymphomas

MALT1: M

ucosa-associated lymphoid tissue lymphoma

translocation gene 1

MRSA: M

ethicillin-resistant Staphylococcus aureus

NEMO: N

F-kB essential modulator

NF-kB: N

uclear factor of kappa light polypeptide gene

enhancer in B cells

PDK1: P

yruvate dehydrogenase kinase, isozyme 1

PHA: P

hytohaemagglutinin

PID: P

rimary immunodeficiency disease

PKC: P

rotein kinase C

PKC-b: P

rotein kinase C, beta type

PKC-u: P

rotein kinase C, theta type

PLC: P

hosphlipase C

PMA: P

horbol 12-myristate 13-acetate

SCID: S

evere combined immunodeficiency

SLP-76: L

ymphocyte cytosolic protein 2

SYK: S

pleen tyrosine kinase

TAK1: T

ransforming growth factor beta-activated

kinase 1

TCR: T

-cell receptor

TEC: T

ec protein tyrosine kinase

TRAF6: T

NF receptor–associated factor 6

TREC: T

-cell receptor excision circle

VZV: V

aricella zoster virus

ORAI calcium release-activated calcium modulator 1 (ORAI1)mutations, which defined a new class of calcium channels.6

The increasing accessibility of next-generationDNA sequencinghas accelerated the genetic characterization of many human PIDs.7

In the past 18 months, a number of independent groups have begunto define novel PIDs caused by defects in the caspase recruitment

domain family, member 11 (CARD11)–B-cell chronic lymphocyticleukemia/lymphoma 10 (BCL10)–mucosa-associated lymphoidtissue lymphoma translocation gene 1 (MALT1 [CBM]) com-plex.8-12 For this ‘‘Current perspectives’’ article, we have engagedexperts in both basic biology and clinical immunology to capturethe worldwide experience in recognizing and managing patientswith PIDs caused by CBM mutations.

CBM SIGNALOSOME COMPLEX AND NUCLEAR

FACTOR kB ACTIVATION IN LYMPHOID IMMUNE

CELLSThe transcription factor nuclear factor kB (NF-kB) is a chief

regulator of lymphocyte activation, survival, and proliferation.The clinical relevance of NF-kB signaling is highlighted by PIDscaused by disabling mutations in the pathway, as well as by theassociation between aberrant constitutive NF-kB activation andinflammatory, autoimmune, and neoplastic disorders.13-15 Overthe past several decades, assembly of the CBM signalosomecomplex has emerged as an essential step in regulating NF-kBin lymphoid immune cells.16-18

Initial insights gained through the study of lymphoma haveprofoundly informed our current appreciation of the CBMcomplex. In the 1990s, B-cell lymphomas affecting themucosa-associated lymphoid tissue (MALT lymphomas) werenoted to be associated with several recurring chromosomaltranslocations, including t(1;14)(p22;q32) and t(14;18)(q32;q21). These translocations bring the BCL10 and MALT1genes, respectively, under the control of the immunoglobulinheavy locus (IgH) enhancer of chromosome 14, leading to dysre-gulated expression of BCL10 or MALT1 (which is also known asparacaspase).17 An additional translocation, t(11;18)(q21;q21), isalso frequently found in patients with MALT lymphomas.17 Thistranslocation creates a gain-of-function fusion protein, inhibitorof apoptosis 2 (IAP2)–MALT1, consisting of the carboxyterminus of MALT1 linked to the amino terminus of cellularIAP2. IAP2-MALT1 can drive constitutive activation of thecanonical NF-kB pathway, promoting cell growth and survival.19

At the biochemical level, BCL10 and MALT1 were found todirectly interact with one another and to synergistically activatethe NF-kB pathway on ectopic expression.19 At the same time,another protein, CARD11 (also called CARD-containingMAGUK protein 1 [CARMA1]), was found to interact withBCL10 and to promote NF-kB activation.20 Finally, in vivo datafrom the analysis of genetically engineered mice with targeteddisruptions of Bcl10,Malt1, orCard11 revealed that all 3 proteinsare essential for adaptive immunity and specifically required tomediate NF-kB activation after B- and T-cell antigen receptor(AgR) stimulation.16,18,21,22

AgR-mediated NF-kB signaling is initiated by the activation ofthe Src family of protein tyrosine kinases, which phosphorylateITAMs within AgR signaling chains, driving the recruitment andactivation of the SYK family kinases, SYK or ZAP-70 (for aschematic overview, see Fig 1; all abbreviations are defined in theAbbreviations used box).23,24 Subsequently, the adaptor proteins—LAT and SLP-76 in T cells, or BLNK in B cells—associatewith the activated AgR complex and recruit further mediators,such as the Tec kinases, ITK (T cells), and BTK (B cells), foractivation of phospholipase Cg1 and Cg2, respectively.25 Theseevents trigger a cascade of downstream events, such as theformation of inositol-1,4,5-trisphosphate (IP3) and diacylglycerol

FIG 1. Schematic overview highlighting the central role of the CBM complex linking AgR activation to NF-kB

activation. BCR, B-cell receptor; BLNK, B-cell linker protein; DAG, diacylglycerol; IP3, inositol-1,4,5-

trispohsphate; ITK, IL-2–inducible T-cell kinase; PIP2, phosphatidylinositol 4,5-bisphosphate; SRC, Src

family kinase.

FIG 2. Schematic overview of the protein domain structure and interactions

between CBM complex members.

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278 TURVEY ET AL

(DAG) as second messengers, which lead to the release ofintracellular calcium and the activation of the serine/threonineprotein kinases, protein kinase C (PKC) u in T cells and PKC-bin B cells, and their recruitment to the AgR complex.26,27

CARD11 is recruited to the immunologic synapse, where it isphosphorylated in the linker region by PKC-u in T cells andPKC-b in B cells.28-30 Additional kinases, including PDK1,Akt, TAK1, CK1alpha and IKK, can also associate with andphosphorylate CARD11.31 Phosphorylation of the linker regionof CARD11 is believed to induce a conformational change withinthe CARD11 molecule, relieving autoinhibition and allowing therecruitment of BCL10 to CARD11. BCL10 itself is constitutivelyassociated with MALT1, and hence the trimeric protein complexcomposed of CARD11, BCL10, and MALT1 is formed.32

CARD11 and BCL10 interact through their N-terminal CARDdomains, whereas the Ser/Thr-rich C-terminal portion ofBCL10 associates with the immunoglobulin-like domains ofMALT1.33 CARD11 may also directly interact with the paracas-pase domain of MALT1 (Fig 2).34 Recent data suggest thatCARD11 induces BCL10 to oligomerize into helical filamentousstructures, which form a platform for the downstream signalingevents of the CBM complex.33 Although CARD11 is onlyexpressed in the hematopoietic system and appears to be specificfor signaling through the T-cell receptor (TCR) and B-cellreceptor (BCR), BCL10 and MALT1 are much more broadlyexpressed. Consequently, other CARD proteins replaceCARD11 and interact with BCL10 and MALT1 to form aCBM complex in other cells, inducing NF-kB activation in

receptor-signaling pathways. For example, CARD10 (also knownas CARMA3) contributes to NF-kB activation throughcell-surface G protein–coupled receptors and receptor tyrosinekinase pathways, and CARD9 is involved in some innate immuneresponses and the C-type lectin receptor pathway (as reviewed inRosebeck et al17 and Jiang and Lin35). Currently, the exactmechanism by which BCL10 and MALT1 regulateIKK-mediated NF-kB activation is not completely understood.However, MALT1 can act as a scaffold protein for the inductionof downstream signaling events (Fig 1). The association ofMALT1 with TNF receptor–associated factor 6 (TRAF6)–containing ubiquitin ligase complexes results in the addition of

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K63-linked ubiquitin chains to a multitude of proteins, includingTRAF6, BCL10, MALT1, and the IKK regulator NF-kBessential modulator (NEMO).36 Linear ubiquitin chains are alsoconjugated to NEMO through the linear ubiquitin chain assemblycomplex (LUBAC), which was recently shown to interact withthe CBM complex in B-cell lymphomas.37,38 Both types ofubiquitination events are essential for the recruitment andactivation of the IKK complex, which can then phosphorylatethe NF-kB inhibitor nuclear factor of k light polypeptide geneenhancer in B-cell inhibitor a (IkBa).39 In resting cells IkBa ismainly bound to NF-kB dimers, keeping those transcriptionfactors inactive in the cytoplasm. Upon phosphorylation by theIKK complex, IkBa is modified by K48-linked ubiquitin chainsand subsequently degraded by the proteasome, resulting in thetranslocation of NF-kB dimers from the cytoplasm to thenucleus, where they can mediate transcription of a large set ofimmunity-relevant target genes.40

Within the CBM signaling complex, the paracaspase MALT1serves also as a caspase-like protease that shares structuralhomology with the family of caspase-like proteins known asmetacaspases found in yeast, plants, and parasites.41 Likemetacaspases, MALT1 cleaves substrates after arginine residues,indicating that the enzymatic cleavage activity is quitedistinct from that of caspases, which in general require anaspartate at the P1 position. Although initial attempts to showa caspase-like activity of MALT1 were unsuccessful, mutationsin the predicted active-site cysteine 464 residue impairedoptimal activation of NF-kB, suggesting an important biologicalrole for MALT1-mediated proteolysis.41 It was not until 2008that the first paracaspase substrates were identified. The list ofsubstrates is still growing and includes BCL10, A20, CYLD,RelB, and Regnase-1.17,42-47 MALT1 can cleave BCL10 toregulate cell adhesion to fibronectin.42 The ubiquitin editingprotein, A20, normally functions to remove K63-linkedubiquitin chains from NF-kB activators, such as TRAF6,NEMO, and MALT1, to provide a negative feedback loop withinthe NF-kB pathway.43 By cleaving and inactivating A20,MALT1 contributes to the amplification and prolongation ofthe NF-kB signal.43 MALT1 can also cleave the deubiquitinat-ing enzyme CYLD and thereby positively regulate JNKsignaling.44 Similarly, MALT1 cleaves the NF-kB subunitRelB to enforce canonical NF-kB signaling,48 and it cleavesthe RNA-binding protein Regnase-1, freeing T cells fromRegnase-1–mediated suppression that regulates the mRNAstability of multiple immune effector genes.47

CBM COMPLEX MUTATIONS AS A NOVEL CAUSE

OF HUMAN COMBINED IMMUNODEFICIENCYCombined immunodeficiency disorders (CIDs) are a spec-

trum of human diseases affecting cellular and humoral immuneresponses, which typically predispose patients to opportunisticinfections.1,49,50 The most severe form of CID presents as SCIDin infancy with pneumonitis, chronic diarrhea, and failure tothrive and is often characterized by absence of functional Tlymphocytes with or without B-cell deficiency. Recently, inaddition to hypomorphic variants of classic SCID-associatedgenes (eg, variants of recombination-activating genes 1 and2), mutations in an increasing number of new genes havebeen identified, leading to a delayed onset of CID often associ-ated with disturbed T-cell homeostasis and function rather than

the absence of T cells.1,51 These patients often have a morevariable clinical phenotype and have been a challenging groupin terms of both diagnosis and therapeutic approach.49 Recentdiscoveries add CBM mutations to the growing list of geneticdefects that must be considered in the differential diagnosisof CID.

The NF-kB family of transcription factors governs keyproliferation, anti-apoptosis, and immune function genes. Notsurprisingly, overactiveNF-kB is often associatedwith oncogenicsignaling and particularly B-cell malignancy. Gain-of-functionsomatic mutations (ie, alterations in DNA that occur afterconception that are neither inherited nor passed to offspring) inthe CBM complex and related NF-kB pathway signalingmolecules have now been convincingly linked to the developmentof B-cell malignancies (extensively reviewed by Shaffer et al52).Therefore our focus will be on the recent discovery of germlinemutations (ie, heritable alterations in DNA in germ cells thatcan be passed to subsequent generations) affecting the CBMcomplex to cause human PIDs (Tables I and II). These novelPIDs have a phenotype that is quite distinct from other knownPIDs that affect the NF-kB axis, such as mutations in IKBKG(or NEMO),53 NFKBIA,54 and IKBKB.55

CARD11 mutationsLoss-of-function mutations (OMIM #615206). Loss-of-

function mutations in CARD11 were the first to be discovered inthe CBM complex.10,11 The original reports independentlydescribed 2 children of Palestinian and central European descentpresenting with hypogammaglobulinemia and Pneumocystisjirovecii pneumonia (PjP) at 13 and 6 months of life, respectively,preceded by recurrent respiratory tract infections in thePalestinian patient. The family history of the Palestinian patientwas notable for consanguineous parents and 2 siblings who haddied at 3 and 15 months of age because of severe respiratorydistress of unknown origin, likely PjP, although no specificdiagnosis was established.

Since the original reports, we are aware of one more child withCARD11 deficiency (B. Neven, unpublished data). This malepatient of French descent presented at the age of 6 months withPjP. He additionally had severe eczematous dermatitis and naildystrophy. No other comorbidities, especially no autoimmunityor lymphoproliferation, have been reported in patients withCARD11 deficiency.

The CARD11 mutations in patients 1 and 2 were identified bymeans of whole-exome sequencing, whereas CARD11 wassequenced in patient 3 as a candidate gene based on clinicaland immunologic phenotype. The mutations and their molecularcharacterization are summarized in Table II.8-12

Two of the 3 patients experienced progressive hypogamma-globulinemia, and 1 presented with agammaglobulinemia at theage of 6 months. Importantly, standard immunologic character-ization demonstrated normal total T- and B-cell numbers(3/3 patients), normal naive T-cell numbers (3/3 patients), andnormal T-cell receptor excision circle (TREC) numbers (tested inonly 1 patient). Therefore clinicians should be aware that thisphenotype might escape detection by both classic diagnostic testsfocused on lymphocyte subsets and TREC-based newbornscreening for SCID. The major consistent phenotypic abnormal-ities related to CARD11mutations were the absence of regulatoryT cells, as previously observed inCard112/2mice,56 and a severeblock in peripheral B-cell differentiation. In patients with

TABLE I. Clinical and immunologic phenotypes and clinical outcomes of autosomal recessive CARD11 and MALT1 mutations

Autosomal recessive CARD11 mutations Autosomal recessive MALT1 mutations

Clinical phenotype

Infections d P jirovecii pneumonia

d Recurrent sinopulmonary bacterial infections

d Recurrent sinopulmonary infections resulting in

bronchiectasis; organisms included: Streptococcus

pneumoniae, Haemophilus influenzae, Klebsiella

pneumoniae, Staphylococcus aureus, Pseudomonas

aeruginosa, Candida albicans, and cytomegalovirus

Autoimmunity/inflammatory

disease

d Severe eczematous dermatitis reported in 1 patient d Widespread inflammatory gastrointestinal disease

with predominantly T-cell lymphocytic infiltration

d Severe eczematous dermatitis

Lymphoproliferation d None d None

Other notable features d None reported to date d Low bone mineral density with recurrent pathologic

fractures

d Profound failure to thrive affecting both height and

weight

Immunologic phenotype

Cellular immunity d Normal T-cell numbers with abnormal proliferation

after anti-CD3/CD28 stimulation, normal naive

T-cell numbers, normal TREC copy numbers, and

normal TCR repertoire

d Normal B-cell and KREC copy numbers but

disordered B-cell development with a block at late

transitional B-cell stage and lack of mature B cells

d Defective NF-kB activation after BCR/TCR and

PMA stimulation

d Reduced numbers of Treg and TH17 cells

d Normal numbers of NK cells

d Normal T-cell numbers but reduced T-cell proliferation

d Variable B-cell numbers with developmental arrest

at the transitional and mature naive stage and absence

of marginal zone B cells

d Defective NF-kB activation after BCR/TCR and PMA

stimulation

d Normal numbers of Treg and TH17 cells

d Normal numbers of NK cells

Humoral immunity d Progressively worsening panhypogammaglobulinemia

with inability to produce specific antibodies

d Normal immunoglobulin levels

d Variable ability to produce specific antibody against

protein and polysaccharide antigens

Clinical outcome

d Fatal in first 2 y of life without specific treatment

d Immune competence restored with hematopoietic

stem cell transplantation

d Fatal in first 2 decades of life without specific treatment

This table is based on both published and unpublished data from the authors.

BCR, B-cell receptor; KREC, kappa-deleting recombination excision circle; NK, natural killer; Treg, regulatory T.

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280 TURVEY ET AL

CARD11 deficiency, memory B cells did not develop, and a largeproportion of the naive B cells displayed a transitionalCD101CD38hi phenotype. Discordant findings seen only insingle patients included monocytopenia and high IgE serumlevels that normalized over time.

Detailed functional analysis revealed a complete loss of AgR-and phorbol 12-myristate 13-acetate (PMA)–induced canonicalNF-kB activation in B and T cells of both published patients.CARD11 deficiency was associated with a severe proliferativedefect in T cells after anti-CD3/CD28 in all 3 patients, whereasthe response to PHAwas preserved in 2 of them. Both publishedpatients had reduced TH1 and TH17 cytokine production, whereasTH2 cytokine levels were not consistently reduced. Given normalNF-kB signaling downstream of CD40 and preserved plasmablastdifferentiation after CD40 and IL-21 stimulation in vitro, thesevere antibody deficiency cannot be completely explained bythe B-cell intrinsic defect. A more complex disturbance of thedifferentiation of plasma cells in vivo related to disrupted T-Binteractions might have contributed to the progressively severehypogammaglobulinemia experienced by all patients.

CARD11-deficient patients have a profound combinedimmunodeficiency, as highlighted by their early-life susceptibilityto PjP. Therefore the principal treatment goal should be rapid and

definitive immune reconstitution with allogeneic hematopoieticstem cell transplantation. As a bridge to transplantation, patientsshould receive immunoglobulin replacement and PjP prophylaxis.After conditioning involving busulfan (myeloablative dose),fludarabine, and antithymocyte globulin, patients 1 and 3 havereconstituted, and no subsequent complications have been reported.The skin disease of patient 3 went into long-term remission. Patient2 had pulmonary disease and received a reduced-toxicityconditioning regimen consisting of treosulfan, fludarabine, andalemtuzumab. This patient achievedmixed chimerism after severaltransfusions of donor lymphocytes. No clinical complications havebeen observed. At this time, the patients are 14, 30, and 15 monthsafter transplantation, respectively.

In summary, loss-of-function CARD11 mutations typicallypresent with progressive hypogammaglobulinemiawithin the firstyear of life. PjP is the leading infectious threat in these patients.Unfortunately, classic diagnostic approaches and TREC-basednewborn screening might not identify the profound combined im-munodeficiency in these patients, which could potentially delayperforming the essential hematopoietic stem cell transplantation.

Gain-of-function mutations (OMIM #606445).

Recently, germline heterozygous gain-of-function mutations inCARD11 have been linked to a novel congenital B-cell

TABLE II. Summary of human germline mutations in CARD11 and MALT1

Race/ethnicity Mutation Effect on protein Reference

Loss-of-function CARD11

mutations causing CID

Patient 1 Palestinian Homozygous 1377-bp genomic

deletion, including entire

sequence for exon 21 of

CARD11

Absent Stepensky et al10

Patient 2 German of central

European ancestry

Homozygous premature stop

codon mutation (c.2833C>T)

p.Q945*

Truncated protein without

GUK domain

Greil et al11

Patient 3 White French Compound heterozygous

(c.1091G>A) p.R364H and

(c.2671C>T) p.891X

Analysis ongoing Unpublished (B. Neven,

A. Durandy, A. Fischer)

Gain-of-function CARD11

mutations causing BENTA

Patient 1-3 White Heterozygous missense mutation

(c.401A>G) p.E134G

Spontaneous aggregation

and signaling

Snow et al12

Patient 4 Chinese Heterozygous missense mutation

(c.367G>A) p.G123S

Spontaneous aggregation

and signaling

Snow et al12

Patient 5 White Heterozygous missense mutation

(c.146G>A) p.C49Y

Spontaneous aggregation

and signaling

Unpublished (D. Buchbinder,

A. Snow)

Patient 6 White Heterozygous missense mutation

(c.368G>A) p.G123D

Spontaneous aggregation

and signaling

Unpublished (J. Moscow,

A. Snow, J. Khan)

Loss-of-function MALT1

mutations causing CID

Patients 1 and 2 Lebanese Homozygous missense mutation

(c. 266G>T) p.S89I

Absent Jabara et al8

Patient 3 Kurdish Canadian Homozygous missense mutation

(c.1739G>C) p.W580S

Very low-level expression

with disruption of

paracaspase and scaffold

functions

McKinnon et al9

Characteristics of human germline mutations identified to date in CARD11 and MALT1.

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lymphoproliferative disorder referred to as B-cell expansionwith NF-kB and T-cell anergy (BENTA).12 Patients with BENTAhave massive B-cell lymphocytosis within the first year oflife, with associated splenomegaly and lymphadenopathy. Theunremarkable appearance of small resting lymphocytes inthe blood generally rules out a diagnosis of overt leukemia, andthe mild anemia and thrombocytopenia noted in some patientshave been attributed to splenic sequestration. Despite excessiveB-cell accumulation, manifestations of autoimmunity are largelyabsent. Mild immunodeficiency is characteristic of BENTAdisease, perhaps relating to intrinsic B- and T-cell signalingabnormalities. Specific infections have included recurrentsinopulmonary and viral infections (molluscum contagiosum,BK virus, and Epstein-Barr virus).

Immunologic phenotyping of patients with BENTA confirmsthat approximately 50% to 80% of PBMCs are CD191

CD201CD5int B cells (approximately 4000-9000 cells/mL;normal, 390-1400 cells/mL), representing mainly polyclonalIgDhi naive mature B cells, with a significant increase inCD101CD24hiCD38hi transitional B-cell numbers, whereasabsolute T-cell counts fall within or just above normal ranges.Congruently, histologic analysis reveals marked follicularhyperplasia with striking accumulation of IgD1 B cells in mantlezones. Several phenotypic features suggest B-cell differentiationmight be partially impaired in patients with BENTA, including(1) very low percentages of circulating memory and class-switched B cells (although absolute counts might be within

normal range); (2) poor immunoglobulin secretion and plasma-blast differentiation in vitro; and (3) incomplete and transienthumoral responses to T cell–independent, polysaccharide-basedvaccines reminiscent of specific antibody deficiency.57 A fewpatients also do not mount protective antibody titers to othervaccines, including measles and varicella zoster virus. Mostpatients exhibit low serum IgM levels, whereas total IgGand IgA levels typically fall at the low end of normal range.Additionally, both CD41 and CD81 T cells from patients withBENTA are hyporesponsive ex vivo unless robust costimulationis provided. Poor proliferation and IL-2 secretion upon mitogenicstimulation suggests patients’ T cells are mildly anergic, whichmight contribute to defects in T-cell help, vulnerability to certainviral infections, or both. These hallmarks surprisingly suggestthat gain-of-function CARD11 mutations create a unique stateof combined immunodeficiency in patients with BENTA,although one that is far less severe than that experienced bypatients with loss-of-function mutations.

To date, 6 patients with BENTA have been identified, allharboring germline gain-of-function mutations in CARD11.These heterozygous missense mutations typically reside withinthe coiled-coil (CC) or LATCH domain of CARD11 protein,with 1 mutation found in the CARD domain. Somatic mutationstypically restricted to the CC region of CARD11 have beendescribed in several forms of diffuse large B-cell lymphoma(DLBCL) that exhibit increased expression of NF-kB–dependentgenes.58-61 These mutations are thought to decouple TCR/BCR

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triggered phosphorylation of the regulatory linker domain fromCC-dependent CBM complex assembly and oligomerization,resulting in spontaneous CBM signalosome formation andconstitutive NF-kB activation.62,63

BENTAdisease is currentlymanaged withminimal therapeuticintervention and close monitoring for infections and any signs ofoligoclonal or monoclonal B-cell expansion. Indeed, it is likelythat patients with BENTA face an increased predisposition toB-cell malignancy (with 1 patient having B-cell chroniclymphocytic leukemia (B-CLL) at around age 44 years), althoughtheir CARD11 mutations alone do not appear to be capable ofoutright B-cell transformation. Interestingly, peripheral B-cellcounts increased sharply in 2 patients who underwent splenec-tomy (absolute lymphocyte count, approximately 100,000 cells/mL; normal absolute lymphocyte count, 1000-5000 cells/mL),suggesting this approach will not reduce B-cell burden. Theutility of B cell–depleting agents, such as rituximab, or othergeneral immunosuppressive drugs remains to be determined.Newer drugs under investigation for the treatment of certainDLBCL, including lenalidomide andMALT1 protease inhibitors,might represent options to specifically target the activity of theCBM signaling pathway.

MALT1 mutationsTo date, autosomal recessive loss-of-function mutations in

MALT1 have been identified in 3 patients with CID, causing aclinical syndrome of recurrent sinopulmonary infections,inflammatory gastrointestinal disease, periodontal disease,dermatitis, and failure to thrive associated with abnormal cellularand humoral immunity (OMIM #615468).

The first 2 cases were female and male siblings born tofirst-cousin parents of Lebanese origin.8 Both patients experi-enced recurrent bacterial pulmonary infections from an earlyage, resulting in bronchiectasis. They also had mastoiditis,chronic aphthous ulcers, cheilitis, and gingivitis. Endoscopicexaminations revealed widespread gastrointestinal inflammation.Their growth was delayed, but neurologic development wasnormal. Both patients died at 7 and 13.5 years of age, respectively,from respiratory failure secondary to recurrent infections. Theonly documented immune-restorative therapy administered wasprophylactic intravenous immunoglobulins.

Immunologic studies revealed normal absolute lymphocytecounts, as well as normal percentages of CD31, CD41, andCD81 T cells; CD41CD45RA1 and CD41CD45RO1 T cells;and CD191 B cells. Lymphocytes had impaired proliferation tocommon mitogens. Serum immunoglobulin levels were normal,but there was no production of isohemagglutinins or anti-tetanusand anti-pneumococcal antibodies, despite vaccination. Geneticstudies combining microarray analysis with whole-genomesequencing revealed a homozygous missense mutation inMALT1 (c. 266G>T) that resulted in an amino acid change fromserine to isoleucine at position 89 in the MALT1 death domain,rendering the mutant protein susceptible to degradation. Thepatients were able to make normal levels of MALT1 mRNA, butimmunoblotting of primary T-cell lysates did not detect anyMALT1 protein. The lack of functional MALT1 protein wasconfirmed by the severe impairment of IkBa degradation and IL-2 production in primary T cells after stimulation and the inabilityof the patients’ MALT1 mutation to correct defective NF-kBactivation and IL-2 production in Malt1-deficient mouse T cells.

At the same time, an independent group identified a case ofhuman MALT1 deficiency in a 15-year-old girl born tofirst-cousin parents of Kurdish descent.9 She experiencedsignificant growth delay, with short stature, low weight, anddelayed bone age. Pathologic fractures might prove to be anadditional feature of human MALT1 deficiency because she hadvery low bone mineral density and fractured her femur and bothtibiae after low-impact injuries. Also, she had frequent viraland bacterial respiratory tract infections that contributed to thedevelopment of chronic inflammatory lung disease, bronchiec-tasis, and nail clubbing. Severe inflammatory gastrointestinaldisease necessitated aNissen fundoplication, repeated esophagealstricture dilatation, and elemental formula feeding througha jejunostomy. She also had widespread excoriated andlichenified dermatitis complicated by methicillin-resistantStaphylococcus aureus and herpes simplex virus superinfection,chronic cheilitis, and gingivitis. Indeed, a case report describingthe patient’s dental challenges was published in 2005 before aspecific molecular diagnosis had been made.64

The absolute lymphocyte count was normal. In contrast to theother 2 MALT1-deficient patients, the patient had severe B-celllymphopenia with a developmental arrest characterized byreduced transitional B cells but increased percentages of naiveIgD1IgM1CD272 B cells, near-absent IgD1IgM1CD271

marginal zone B cells, and reduced IgD2IgM2CD271 switchedmemory B cells. However, serum immunoglobulin levelswere normal (except for a chronically increased IgE level),with protective antibody titers after vaccination, as well asisohemagglutinins.

Whole-exome sequencing revealed a homozygous missensemutation in MALT1 (c. 1739G>C) that converts a tryptophan toserine at position 580, resulting in normal MALT1 mRNAexpression but very low expression of MALT1 protein.Functional impairment was demonstrated by the absence ofparacaspase activity, disruption of the constitutive associationbetween MALT1 and BCL10, and absent IkBa degradationand p65/RelA phosphorylation in primary T cells after PMA/ionomycin stimulation. Importantly, artificial expression ofnormal MALT1 protein in the patient’s primary T cells rescuedtheir ability to activate NF-kB.

At this time, because of the very limited number of publishedcases of human MALT1 deficiency, it is not possible to providedefinitive guidance on treatment options. However, based onMALT1 biology, immune function should be able to be restored inMALT1-deficient patients after allogeneic hematopoietic stemcell transplantation.

Unifying clinical features of loss-of-function CBM

complex mutationsFrom a clinical perspective, features that should raise suspicion

for loss-of-function mutations affecting the CBM complexinclude CID with normal T-cell numbers, abnormal T-cellproliferation, and failure to activate NF-kB after stimulationwith PMA. Although more patients with CBM complex muta-tions need to be identified before firm conclusions can be drawn,defective B-cell development with a transitional B-cell block isalso likely to be a defining feature because this is a unifyingphenotype ofMalt12/2,Card112/2, andBcl102/2mice.16,18,21,65

Given the normal T-cell numbers, TREC-based newbornscreening might well not identify patients with mutations in the

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CBM complex. Therefore when there is a clinical suspicion of aCBM mutation and standard testing reveals a failure ofTCR stimulation-induced proliferation, more specific testsshould be pursued, including assessment of PMA-inducedNF-kB activation and genetic testing.

Intriguing differences between the clinical presentation ofhuman CARD11 and MALT1 deficiency suggest that the CBMmembers might have individual nuanced and independentfunctions, perhaps related to the fact that CARD11 expressionis restricted to hematopoietic cells, whereas MALT1 is morebroadly expressed. Nevertheless, many questions remainunanswered. Why is PjP so prominent in patients withCARD11 but not MALT1 deficiency? Why is gastrointestinalinflammation a defining aspect ofMALT1mutations? Ultimately,these insights into human biology will be answered through thediagnosis and detailed immunologic characterization of morepatients with mutations affecting the CBM complex.

ConclusionsThe NF-kB family of transcription factors plays a crucial role

in immune cell activation, survival, and proliferation. AberrantNF-kB activity is associated with a range of human diseases,including cancer, immunodeficiency, and autoimmunity. TheCBM signalosome complex links AgR triggering to NF-kBactivation. Empowered by next-generation sequencing technol-ogy, very recently, a number of independent groups haveconfirmed that germline mutations affecting the CBM complexare the cause of novel combined immunodeficiency phenotypesthat all share abnormal NF-kB activation and dysregulated B-celldevelopment as defining features. Informed by these recentdiscoveries, it is anticipated that many additional patients withCBM mutations will receive diagnoses over time.

Beyond the benefits individual patients and their familiesexperience after a specific molecular diagnosis, there is a richhistory of key discoveries in fundamental biology emerging fromthe identification of PID-causing genes. Today, there is consider-able interest in developing MALT1 inhibitors for treatment oflymphomas ‘‘addicted’’ to NF-kB signaling through the CBMcomplex,66 although the in vivo protease function of MALT1 isstill not well characterized. However, because inhibition of theCBM complex and MALT1 protease activity also impair optimalNF-kB activation and IL-2 production in T cells,8,9,42 inhibitorsthat selectively target CBM complex activity might be promisingcandidates for clinical use in many immune diseases, such asallergic inflammation, autoimmunity, and rejection of trans-planted tissues. Ultimately, a deeper understanding of the clinicaland immunologic effect of human mutations in the CBMsignalosome will be invaluable in guiding the development ofCBM complex inhibitors for broad therapeutic applications.

Clinical implications: Mutations in the CBM signalosome com-plex must be considered in the differential diagnosis of patientswith the clinical presentation of CID.

REFERENCES

1. Al-Herz W, Bousfiha A, Casanova JL, Chapel H, Conley ME, Cunningham-

Rundles C, et al. Primary immunodeficiency diseases: an update on the

classification from the international union of immunological societies expert

committee for primary immunodeficiency. Front Immunol 2011;2:54.

2. Bennett CL, Christie J, Ramsdell F, Brunkow ME, Ferguson PJ, Whitesell L,

et al. The immune dysregulation, polyendocrinopathy, enteropathy, X-linked

syndrome (IPEX) is caused by mutations of FOXP3. Nat Genet 2001;27:20-1.

3. Wildin RS, Ramsdell F, Peake J, Faravelli F, Casanova JL, Buist N, et al.

X-linked neonatal diabetes mellitus, enteropathy and endocrinopathy syndrome

is the human equivalent of mouse scurfy. Nat Genet 2001;27:18-20.

4. Finnish-German APECED Consortium. An autoimmune disease, APECED,

caused by mutations in a novel gene featuring two PHD-type zinc-finger domains.

Nat Genet 1997;17:399-403.

5. Nagamine K, Peterson P, Scott HS, Kudoh J, Minoshima S, Heino M, et al.

Positional cloning of the APECED gene. Nat Genet 1997;17:393-8.

6. Feske S, Gwack Y, Prakriya M, Srikanth S, Puppel SH, Tanasa B, et al.

A mutation in Orai1 causes immune deficiency by abrogating CRAC channel

function. Nature 2006;441:179-85.

7. Platt C, Geha RS, Chou J. Gene hunting in the genomic era: approaches to

diagnostic dilemmas in patients with primary immunodeficiencies. J Allergy

Clin Immunol 2014;134:262-8.

8. Jabara HH, Ohsumi T, Chou J, Massaad MJ, Benson H, Megarbane A, et al.

A homozygous mucosa-associated lymphoid tissue 1 (MALT1) mutation in a

family with combined immunodeficiency. J Allergy Clin Immunol 2013;132:

151-8.

9. McKinnon ML, Rozmus J, Fung SY, Hirschfeld AF, Del Bel KL, Thomas L, et al.

Combined immunodeficiency associated with homozygous MALT1 mutations.

J Allergy Clin Immunol 2014;133:1458-62, e1-7.

10. Stepensky P, Keller B, Buchta M, Kienzler AK, Elpeleg O, Somech R, et al.

Deficiency of caspase recruitment domain family, member 11 (CARD11),

causes profound combined immunodeficiency in human subjects. J Allergy Clin

Immunol 2013;131:477-85.e1.

11. Greil J, Rausch T, Giese T, Bandapalli OR, Daniel V, Bekeredjian-Ding I, et al.

Whole-exome sequencing links caspase recruitment domain 11 (CARD11)

inactivation to severe combined immunodeficiency. J Allergy Clin Immunol

2013;131:1376-83.e3.

12. Snow AL, Xiao W, Stinson JR, Lu W, Chaigne-Delalande B, Zheng L, et al.

Congenital B cell lymphocytosis explained by novel germline CARD11

mutations. J Exp Med 2012;209:2247-61.

13. DiDonato JA, Mercurio F, Karin M. NF-kappaB and the link between

inflammation and cancer. Immunol Rev 2012;246:379-400.

14. McDonald DR, Janssen R, Geha R. Lessons learned from molecular defects

in nuclear factor kappaB dependent signaling. Microbes Infect 2006;8:

1151-6.

15. Ben-Neriah Y, Karin M. Inflammation meets cancer, with NF-kB as the

matchmaker. Nat Immunol 2011;12:715-23.

16. Ruland J, Duncan GS, Wakeham A, Mak TW. Differential requirement for Malt1

in T and B cell antigen receptor signaling. Immunity 2003;19:749-58.

17. Rosebeck S, Rehman AO, Lucas PC, McAllister-Lucas LM. From MALT

lymphoma to the CBM signalosome: three decades of discovery. Cell Cycle

2011;10:2485-96.

18. Ruefli-Brasse AA, French DM, Dixit VM. Regulation of NF-kappaB-dependent

lymphocyte activation and development by paracaspase. Science 2003;302:

1581-4.

19. Lucas PC, Yonezumi M, Inohara N, McAllister-Lucas LM, Abazeed ME, Chen

FF, et al. Bcl10 and MALT1, independent targets of chromosomal translocation

in malt lymphoma, cooperate in a novel NF-kappa B signaling pathway. J Biol

Chem 2001;276:19012-9.

20. Gaide O, Martinon F, Micheau O, Bonnet D, Thome M, Tschopp J. Carma1, a

CARD-containing binding partner of Bcl10, induces Bcl10 phosphorylation

and NF-kappaB activation. FEBS Lett 2001;496:121-7.

21. Hara H, Wada T, Bakal C, Kozieradzki I, Suzuki S, Suzuki N, et al. The MAGUK

family protein CARD11 is essential for lymphocyte activation. Immunity 2003;

18:763-75.

22. Ruland J, Duncan GS, Elia A, del Barco Barrantes I, Nguyen L, Plyte S, et al.

Bcl10 is a positive regulator of antigen receptor-induced activation of

NF-kappaB and neural tube closure. Cell 2001;104:33-42.

23. Geahlen RL. Syk and pTyr’d: signaling through the B cell antigen receptor.

Biochim Biophys Acta 2009;1793:1115-27.

24. Love PE, Hayes SM. ITAM-mediated signaling by the T-cell antigen receptor.

Cold Spring Harb Perspect Biol 2010;2:a002485.

25. Readinger JA, Mueller KL, Venegas AM, Horai R, Schwartzberg PL. Tec kinases

regulate T-lymphocyte development and function: new insights into the roles of

Itk and Rlk/Txk. Immunol Rev 2009;228:93-114.

26. Schulze-Luehrmann J, Ghosh S. Antigen-receptor signaling to nuclear factor

kappa B. Immunity 2006;25:701-15.

27. Kong KF, Altman A. In and out of the bull’s eye: protein kinase Cs in the

immunological synapse. Trends Immunol 2013;34:234-42.

J ALLERGY CLIN IMMUNOL

AUGUST 2014

284 TURVEY ET AL

28. Blonska M, Lin X. CARMA1-mediated NF-kappaB and JNK activation in

lymphocytes. Immunol Rev 2009;228:199-211.

29. Sommer K, Guo B, Pomerantz JL, Bandaranayake AD, Moreno-Garcia ME,

Ovechkina YL, et al. Phosphorylation of the CARMA1 linker controls

NF-kappaB activation. Immunity 2005;23:561-74.

30. Shinohara H, Yasuda T, Aiba Y, Sanjo H, Hamadate M, Watarai H, et al.

PKC beta regulates BCR-mediated IKK activation by facilitating the interaction

between TAK1 and CARMA1. J Exp Med 2005;202:1423-31.

31. Roche MI, Ramadas RA, Medoff BD. The role of CARMA1 in T cells. Crit Rev

Immunol 2013;33:219-43.

32. Thome M, Charton JE, Pelzer C, Hailfinger S. Antigen receptor signaling to

NF-kappaB via CARMA1, BCL10, and MALT1. Cold Spring Harb Perspect

Biol 2010;2:a003004.

33. Qiao Q, Yang C, Zheng C, Fontan L, David L, Yu X, et al. Structural architecture

of the CARMA1/Bcl10/MALT1 signalosome: nucleation-induced filamentous

assembly. Mol Cell 2013;51:766-79.

34. Che T, You Y, Wang D, Tanner MJ, Dixit VM, Lin X. MALT1/paracaspase is a

signaling component downstream of CARMA1 and mediates T cell receptor-

induced NF-kappaB activation. J Biol Chem 2004;279:15870-6.

35. Jiang C, Lin X. Regulation of NF-kappaB by the CARD proteins. Immunol Rev

2012;246:141-53.

36. Oeckinghaus A, Wegener E, Welteke V, Ferch U, Arslan SC, Ruland J, et al.

Malt1 ubiquitination triggers NF-kappaB signaling upon T-cell activation.

EMBO J 2007;26:4634-45.

37. Yang Y, Schmitz R, Mitala J, Whiting A, Xiao W, Ceribelli M, et al. Essential role

of the linear ubiquitin chain assembly complex in lymphoma revealed by rare

germline polymorphisms. Cancer Discov 2014;4:480-93.

38. Dubois SM, Alexia C, Wu Y, Leclair HM, Leveau C, Schol E, et al.

A catalytic-independent role for the LUBAC in NF-kappaB activation upon

antigen receptor engagement and in lymphoma cells. Blood 2014;123:2199-203.

39. Duwel M, Hadian K, Krappmann D. Ubiquitin conjugation and deconjugation in

NF-kappaB signaling. Subcell Biochem 2010;54:88-99.

40. Vallabhapurapu S, Karin M. Regulation and function of NF-kappaB transcription

factors in the immune system. Annu Rev Immunol 2009;27:693-733.

41. Uren AG, O’Rourke K, Aravind LA, Pisabarro MT, Seshagiri S, Koonin EV, et al.

Identification of paracaspases and metacaspases: two ancient families of

caspase-like proteins, one of which plays a key role in MALT lymphoma. Mol

Cell 2000;6:961-7.

42. Rebeaud F, Hailfinger S, Posevitz-Fejfar A, Tapernoux M, Moser R, Rueda D,

et al. The proteolytic activity of the paracaspase MALT1 is key in T cell

activation. Nat Immunol 2008;9:272-81.

43. Coornaert B, Baens M, Heyninck K, Bekaert T, Haegman M, Staal J, et al. T cell

antigen receptor stimulation induces MALT1 paracaspase-mediated cleavage of

the NF-kappaB inhibitor A20. Nat Immunol 2008;9:263-71.

44. Staal J, Driege Y, Bekaert T, Demeyer A, Muyllaert D, Van Damme P, et al. T-cell

receptor-induced JNK activation requires proteolytic inactivation of CYLD by

MALT1. EMBO J 2011;30:1742-52.

45. Hailfinger S, Nogai H, Pelzer C, Jaworski M, Cabalzar K, Charton JE, et al.

Malt1-dependent RelB cleavage promotes canonical NF-kappaB activation in

lymphocytes and lymphoma cell lines. Proc Natl Acad Sci U S A 2011;108:

14596-601.

46. Kirchhofer D, Vucic D. Protease activity of MALT1: a mystery unravelled.

Biochem J 2012;444:e3-5.

47. Uehata T, Iwasaki H, Vandenbon A, Matsushita K, Hernandez-Cuellar E,

Kuniyoshi K, et al. Malt1-induced cleavage of regnase-1 in CD4(1) helper

T cells regulates immune activation. Cell 2013;153:1036-49.

48. Hailfinger S, Nogai H, Pelzer C, Jaworski M, Cabalzar K, Charton JE, et al.

Malt1-dependent RelB cleavage promotes canonical NFkB activation in

lymphocytes and lymphoma cell lines. Proc Natl Acad Sci U S A 2011;108:

14596-601.

49. Roifman CM, Somech R, Kavadas F, Pires L, Nahum A, Dalal I, et al.

Defining combined immunodeficiency. J Allergy Clin Immunol 2012;130:

177-83.

50. Shearer WT, Dunn E, Notarangelo LD, Dvorak CC, Puck JM, Logan BR, et al.

Establishing diagnostic criteria for severe combined immunodeficiency

disease (SCID), leaky SCID, and Omenn syndrome: the Primary Immune

Deficiency Treatment Consortium experience. J Allergy Clin Immunol 2014;

133:1092-8.

51. Notarangelo LD. Functional T cell immunodeficiencies (with T cells present).

Annu Rev Immunol 2013;31:195-225.

52. Shaffer AL 3rd, Young RM, Staudt LM. Pathogenesis of human B cell

lymphomas. Annu Rev Immunol 2012;30:565-610.

53. Zonana J, Elder ME, Schneider LC, Orlow SJ, Moss C, Golabi M, et al. A novel

X-linked disorder of immune deficiency and hypohidrotic ectodermal dysplasia is

allelic to incontinentia pigmenti and due to mutations in IKK-gamma (NEMO).

Am J Hum Genet 2000;67:1555-62.

54. Courtois G, Smahi A, Reichenbach J, Doffinger R, Cancrini C, Bonnet M, et al.

A hypermorphic IkappaBalpha mutation is associated with autosomal dominant

anhidrotic ectodermal dysplasia and T cell immunodeficiency. J Clin Invest

2003;112:1108-15.

55. Pannicke U, Baumann B, Fuchs S, Henneke P, Rensing-Ehl A, Rizzi M, et al.

Deficiency of innate and acquired immunity caused by an IKBKB mutation. N

Engl J Med 2013;369:2504-14.

56. Molinero LL, Yang J, Gajewski T, Abraham C, Farrar MA, Alegre ML.

CARMA1 controls an early checkpoint in the thymic development of FoxP31regulatory T cells. J Immunol 2009;182:6736-43.

57. Boyle RJ, Le C, Balloch A, Tang ML. The clinical syndrome of specific antibody

deficiency in children. Clin Exp Immunol 2006;146:486-92.

58. Lenz G, Davis RE, Ngo VN, Lam L, George TC, Wright GW, et al. Oncogenic

CARD11 mutations in human diffuse large B cell lymphoma. Science 2008;

319:1676-9.

59. Lohr JG, Stojanov P, Lawrence MS, Auclair D, Chapuy B, Sougnez C, et al.

Discovery and prioritization of somatic mutations in diffuse large B-cell

lymphoma (DLBCL) by whole-exome sequencing. Proc Natl Acad Sci U S A

2012;109:3879-84.

60. Dong G, Chanudet E, Zeng N, Appert A, Chen YW, Au WY, et al. A20, ABIN-

1/2, and CARD11 mutations and their prognostic value in gastrointestinal diffuse

large B-cell lymphoma. Clin Cancer Res 2011;17:1440-51.

61. Montesinos-Rongen M, Schmitz R, Brunn A, Gesk S, Richter J, Hong K, et al.

Mutations of CARD11 but not TNFAIP3 may activate the NF-kappaB pathway

in primary CNS lymphoma. Acta Neuropathol 2010;120:529-35.

62. Chan W, Schaffer TB, Pomerantz JL. A quantitative signaling screen identifies

CARD11 mutations in the CARD and LATCH domains that induce Bcl10

ubiquitination and human lymphoma cell survival. Mol Cell Biol 2013;33:

429-43.

63. Lamason RL, Kupfer A, Pomerantz JL. The dynamic distribution of CARD11 at

the immunological synapse is regulated by the inhibitory kinesin GAKIN. Mol

Cell 2010;40:798-809.

64. Tsang P, Derkson G, Priddy R, Junker AK, Slots J, Larjava H. Severe

periodontitis in a 5-year-old girl with hyperimmunoglobulin E syndrome. Pediatr

Dent 2005;27:68-73.

65. Xue L, Morris SW, Orihuela C, Tuomanen E, Cui X, Wen R, et al. Defective

development and function of Bcl10-deficient follicular, marginal zone and B1

B cells. Nat Immunol 2003;4:857-65.

66. Young RM, Staudt LM. A new ‘‘brew’’ of MALT1 inhibitors. Cancer Cell 2012;

22:706-7.