Renal Diseases in Monoclonal Gammopathies & Cryoglobulinemia

Dr. Pallavi PrasadPDCC Renal PathologySGPGIMS, Lucknow

Nephrotic syndromeCardiomegalyNeuropathy

hepatomegaly

Inflammatory syndromes

Familial historyM-component (serum/urine)

Biopsy of superficial

organ/ kidney

Congo-red

amyloid

LCDDHCDD

Others:IC like

glomerulonephritisImmunotactoid

cryoglobulinemia

+

-

Introduction• Multiple myeloma

• Plasma cell dyscrasias

• MGUS

Immunoglobulins

• Light chains: kappa and lambda( κ and λ)

• Heavy chains: Alpha, Gamma, Mu, Delta and Epsilon (α,

γ,μ,δ,ε)

MetabolismLight chains filtered by

glomerulus

90% reabsorbed by proximal tubule

Catabolized by endolysosomes

Small amount of FLC in urine normally..

Plasma cell dyscrasias

LC overproduction

Precipitate in tubular filtrate

Bence Jones proteins

• Does not meet the criteria for overt myeloma/ B-cell

proliferation

• Overall survival significantly better than that of MM

▫MGUS: treatment is not recommended

▫MGRS: treatment is fundamental

• Transplant: high rates of recurrence in MGRS

Monoclonal gammopathy of renal significance [MGRS]

Monoclonal gammopathy of renal significance• Defined as a causal relationship between a small B-cell clone and

renal damage

• Organized deposits

▫ Fibrillar deposits: Amyloidosis (AL, AH, ALH)

▫ Micro tubular: Type I and type II cryoglobulinemias and

immunotactoid glomerulopathy

• Non-organized deposits

▫ monoclonal immunoglobulin deposits

• Light-chain proximal tubulopathy (with or without Fanconi

syndrome)

Lab features s/o monoclonal gammopathy

• High serum globulin fraction

• Abnormally low anion gap

• Unexplained hyponatremia

• Hypercalcemia

• Hypophosphatemia or hyperphosphatemia

• Fanconi syndrome, distal renal tubular acidosis

Urine analysis

• Light chain proteinuria

• Amyloid : nephrotic range proteinuria + bland urinary

sediments

• MIDD: microscopic hematuria

Lab detection of monoclonal Ig

Immunoelectrophoresis

Immunofixation

Western blotting

Nephelometry : both monomers and dimers of kappa and

lambda (< 2 to 4 mg/L)

Renal Involvement in Plasma Cell Dyscrasias

•Heterogeneous

•~85% of all light chains : nephrotoxic

•~70%) :“tubulopathies”

•~30% :“glomerulopathies”

Renal Involvement in Plasma Cell Dyscrasias

Light chain (myeloma) cast nephropathy

Acute tubulopathy (acute tubular damage or necrosis)

Inflammatory tubulointerstitial nephritis

Amyloidosis (light chain- [AL] or heavy chain- [AH] related amyloidosis)

Deposition diseases (LCDD/HCDD)

I) Acute tubular damage (acute tubulopathy)• Pathogenesis :

• Inability of lysosomal system to degrade nephrotoxic

light chain

• Lysosomal release of proteolytic enzymes into cytosol

• Leading to cytoplasmic vacuolization, simplification, and

necrosis

Light Microscopy

• Proximal tubular damage

• ATN: vacuolization of tubular cells, apical blebbing, loss

of surface microvilli, desquamation, fragmentation

tubular regeneration- mitotic figures

fragmentation and desquamation

Severe tubulopathy-cell necrosis

• Tubulopathy with crystalline inclusion (clinical Fanconi

syndrome)

Immunofluorescence

• Monotypic staining for a type of LC

• In cytoplasm of tubular cells

•Electron microscopy• Large, atypical lysosomes

• Fanconi syndrome = crystalline

Differential Diagnosis

ATN from other causes

II) Inflammatory tubulointerstitial Nephritis

• ~10% of cases

• Acute renal failure

• Non-nephrotic range proteinuria

PathogenesisAlter intrinsic tissue antigens

Release of cytokines

Chemoattraction

Activation of inflammatory cells- TIN

Light Microscopy

• Glomeruli, vessels : unremarkable

• No tubular cast formation

Intense inflammation

Lymphocytes, plasma cells

Tubulitis

Immunofluorescence

• Linear monoclonal light

chain staining along TBM

Immunohistochemistry

for к and λ light chains

Electron Microscopy

• punctate to powdery, electron-dense material along

outer aspect of tubular basement membranes

• Prominent lysosomes

D/D:

• Allergic TIN

Case-1

• 45y/M

• C/O generalised weakness x 6 months

• Off and on fever

• Multiple bone pains

• Advanced rapid renal failure

Cr 6.8 mg/dl

Ca 12 mg/dl

ALP 258U/l

24 hr urinary protein 4.99 gm

Serum electrophoresis M-band in gamma region

Serum Immunofixation IgG lambda monoclonal light chains

Bone marrow biopsy Fibrotic with increased plasma cells (6-8%)

Investigations

Irregular, refractile, angular or geometric shapes with fracture

planes

Weak PAS positivity

Interstitial inflammation

Interstitial fibrosis

III) Light Chain (Myeloma) Cast Nephropathy

• 1st renal lesion to be recognised in myeloma

• Nephrotic range proteinuria [light chains]

• Urine analysis: dipstick test fails to pick up light chain

proteinuria

Pathogenesis

Excess of light chains

distal nephron

Tamm horsfall protein

Co-aggregationcasts

Resistant to metalloproteinas

es

Cytokine release and interstitial

nephritis

• Crystals in some

• Some are congophillic with apple green birefringence

• Thioflavin T, S

Immunofluorescence

• Restricted light chain staining : casts formed acutely

• Trapping of other LC : long duration

Electron microscopy

• Fibrillary material,

granular electron

dense material

• Variably-shaped

crystalline material

(specific)

Differential diagnosis

Nephropathies with cast formation

Rifampin associated light chain proteinuria

Case-2

• 56y/M

• K/C/O hypothroidism

• C/O swelling of lower limbs x 2 yrs

• Joint pains b/l knee joints off and on

• Bleeding per-rectum. On colonoscopy- tuberculous colonic

ulcer

• Nephrotic range proteinuria  and normal S. Creatinine

• Clinical diagnosis ? amyloidosis

Cr 1.1 mg/dl

C3, C4 normal

ANA negative

24 hr urinary protein 3.5 gm

Serum electrophoresis M-band in gamma region

Abdominal fat pad negative

Investigations

eosinophilic, amorphous, hyaline material

Weak PAS positivity

Blood vessel

ATNFoam cells

Tubular atrophy

Congo-red

Apple-green birefringence

lambda

Lambda>kappa

Immunofluorescence

IV) Amyloidosis

• Protein folding disorder

• AL amyloidosis (74%)

• AA amyloidosis: 2nd most common (4%)

• Localised amyloidosis (20%)

• Familial amyloidosis (2%)

• Nephrotic range proteinuria with or without renal failure

Gross Pathology:

• Enlarged kidneys with pale, waxy-

appearing cut surfaces

• Normal/small size

Light Microscopy

• Same regardless of type of amyloid

• In any renal compartments

• Glomeruli : mesangium extending into peripheral

capillary walls and vessels

• Spikes segmental

Diffuse mesangia

l

nodular Pure GBM

Light Microscopy

• Interstitium : deposits, foam cells, lymphoplasmacytic

infiltrate

• Tubules : atrophy (advanced cases)

• Blood vessels : m/c in arterioles. Resembles hyalinosis

or fibrinoid necrosis

Fluorescence with thioflavin T

Immunohistochemistry

Human amyloid P component

К- and λ immunoglobulin light chains

Amyloid A protein

Transthyretin

Fibrinogen

ᵝ2-microglobulin

?AL vs AA amyloid

• Specific antibody

• Potassium permanganate pretreatment

• Eliminate Congo red positivity for AA amyloid but not for

AL amyloid

Electron Microscopy:• Randomly arranged, rigid, nonbranching 8- to 10-nm

diameter fibrils

• Extracellular

• In mesangium peripheral

capillary walls, subendothelial/

subepithelial

Differential diagnosis of amyloid

Pathogenesis of AL amyloid

Pathogenesis of AA amyloid

Case-3

• 20y/m

• C/O swelling over body x 2 months

• Hypertension x 1 month

• Low-grade fever x 1 week

Advanced renal failure

Subnephrotic proteinuria ? MPGN

Cr 6.3 mg/dl

Ca 8.2 mg/dl

Albumin 2.9 g/dl

24 hr urinary protein 4.99 gm

Serum elecrophoresis Bands in albumin, α1, α2,ᵦ . No M band

Kappa/ lambda ratio 3.6

Lambda free LC assay 139 mg/l [5.7-26.3]

Bone marrow biopsy 6-8% plasma cells

Investigations

nodular glomerulopathy

hypercellular nodules

vessels

IHC for к light chain

Thickened tubular basement membranes

ATN

Kappa>lambda

kappa

lambda

Immunofluorescence

V) Monoclonal Immunoglobulin Deposition Disease

• Deposition of monoclonal Ig in many organs

• LCDD

• HCDD

• Combined LHCDD (~10%)

Pathogenesis of LCDD

Light microscopy of LCDD• Other patterns:

▫Mesangial hypercellularity

▫Membranoproliferative

▫Crescent formation

• D/D : early LCDD with minimal change disease

Mesangial LCD

Continuous, punctate, subendothelial & along peri glomerular capillary wall

Along vessel wall

Heavy Chain Deposition Disease (HCDD)

• α-HCD

• Ƴ-HCD (renal disease)

• µ-HCD

• Combined LCDD and HCDD = LHCDD (Ƴ)

Etiology and pathogenesis:Deletions in heavy chain portions (CH1, CH2) of

immunoglobulin molecule

Premature secretion of HC into circulation

structurally abnormal HC

deposit in organs

Light Microscopy• Nodular glomerulosclerosis similar to LCDD• Crescents (11-75%)• TBM deposits• Congo red - negative

Immunofluorescence

• Heavy chains+

• Distribution similar to LCDD

• linear > granular

E/M :Similar to LCDD

• deposition of fibrils 13-18nmDirect immunofluorescence (µ heavy chain)

Differential Diagnosis

Minimal change disease

Mesangial proliferative glomerulonephritis

MPGN

Crescentic glomerulonephritis

Diabetic nephropathy

Idiopathic nodular glomerulosclerosis

Amyloid

Cryoglobulinemic Nephropathy

• Cryoglobulins are serum proteins (immunoglobulins) that

are soluble at 37°C (i.e., monoclonal cryoglobulins)

• Precipitate in the cold and redissolve when heated.

• Precipitate in the vasculature

• Precipitation of cryoglobulins depends on temperature, pH,

cryoglobulin concentration and weak noncovalent factors

• Vasculitis

thrombi

Test for cryoglobulins

• Blood specimen is drawn and maintained at 37°C until

clotting is completed.

• Serum is separated and incubated at 4°C. for 72 hrs.

• Agglutination or gelation = cryoglobulins.

• Type of cryoglobulins :-

• IgM; a/w monoclonal gammopathies, B-cell neoplasms, plasma cell dyscrasias

Type I

• IgM - exhibits activity against the Fc portion of polyclonal IgGType II

• polyclonal immunoglobulinsType III

Light Microscopy

• m/c= Membranoproliferative glomerulonephritis (MPGN)

type I

• Infiltration of capillary spaces by monocytes and

polymorphonuclear cells may also be seen.

Glomerular capillaries completely filled with

thrombi containing cryoglobulins (PAS stain)

Immunofluorescence

a) Strong staining of intraluminal thrombi+granular to

pseudolinear staining along peripheral capillary walls

(most characteristic pattern)

b) Granular to pseudolinear subendothelial staining

• IgG > IgM> C3

Because of the cyclical nature of this disorder, deposits

can be abundant / scanty in a given patient during the

course of the disease.

Immunofluorescence

Electron Microscopy

• Paired, randomly arranged or in groups [paracrystalline

arrays]

• Fingerprints/ fibrillary/ crystalloid substructure

•Classic curved microtubular

Aggregates..

Differential Diagnosis

1) Lupus nephritis

2) Thrombotic microangiopathy (hyaline thrombi)

• The fact that cryoglobulins can be seen in otherwise

typical lupus nephritis further complicates the differential

diagnosis.

• IF, EM, clinical and serologic findings