Recurrent Strokes after VaricellaHaruo Hattori, MD, Yoshihisa Higuchi, MD,and Masahiro Tsuji, MD

Sebire and colleagues1 demonstrated a statistical link betweenan idiopathic arterial ischemic stroke and varicella in chil-dren. We have cared for a child who developed multiplestrokes after varicella, with evidence of persistent intrathecalvaricella-zoster virus (VZV) infection.

A previously healthy boy suffered from uncomplicatedvaricella at the age of 1 year and 3 months. He experiencedtransient right hemiparesis at the age of 1 year and 6months. Magnetic resonance imaging showed a lacunar in-farct in the left putamen and internal capsule. Magnetic res-onance angiography (MRA) revealed mild stenosis in theproximal portion of the left middle cerebral artery (MCA).He began to receive anti-platelet medication. He developedanother transient right hemiparesis at the age of 1 year and11 months. Magnetic resonance imaging showed a new la-cunar infarct in the deep white matter of the left frontal lobeas well as worsening stenosis of the left MCA on MRA. Hewas referred to us at the age of 2 years and 2 months. Neu-rological examinations revealed no abnormalities, except aleft-hand preference. Cerebral angiography showed focal ste-nosis of the M1 segment of the left MCA. The cerebrospinalfluid (CSF) contained 38 lymphocytes per microliter, withnormal concentrations of protein and glucose. IgG antibod-ies against VZV were found by enzyme-linked immuno-sorbent assay in the CSF. VZV DNA was not detected bypolymerase chain reaction. The organism-specific antibodyindex (organism-specific IgG in CSF/total IgG in CSF 4organism-specific IgG in serum/total IgG in serum) was 16for VZV. At a follow-up examination at the age of 2 yearsand 11 months, there had been no more recurrence ofstroke. MRA demonstrated decreasing severity of the stenosisof the left MCA. The CSF showed no pleocytosis and low-ering anti-VZV antibodies.

The CSF of this boy had both pleocytosis and anti-VZVantibodies even 11 months after varicella with a highorganism-specific antibody index. This suggests that the de-layed varicella arteriopathy results from direct viral invasionof the cerebral artery.

Department of Pediatrics, Kyoto University School ofMedicine, Kyoto, Japan

Reference1. Sebire G, Meyer L, Chabrier S. Varicella as a risk factor for ce-

rebral infarction in childhood: a case-control study. Ann Neurol1999;45:679–680

Levodopa Induces a Cytoplasmic Localization ofD1 Dopamine Receptors in Striatal Neurons inParkinson’s DiseaseA. Di Rocco, MD, and P. Werner, PhD

The article by Muriel and co-workers1 describing the changesin D1 receptor localization after dopaminergic treatmentprovides an important insight into the mechanisms underly-

ing the complications of long-term treatment with levodopa(L-dopa). There are, however, a number of points that de-serve additional comments.

Although the results of the animal portion of the study arecompelling, the rationale for treating the animals with a D1dopamine agonist but not L-dopa is not immediately clear.As the animal experiments aimed at replicating the pharma-cological effect observed in autopsied brains of L-dopa–treated parkinsonian patients, it would have been preferableto observe the direct effect of L-dopa stimulation or the dif-ferential effect of selective D1 and D2 receptor agonists inthe lesioned animals.

It would also have been helpful to determine whether thereceptor relocation observed in autopsied brains was relatedto the length or the intensity of receptor stimulation andwhether the degree of receptor internalization correlated withthe duration of L-dopa treatment, disease duration, or con-comitant use of other anti-parkinsonian agents. Two of thepatients were in fact taking unusually low doses of L-dopa(150 and 175 mg/day), despite a long disease duration, sug-gesting that other anti-parkinsonian drugs may have beenused. This is of great importance as speculation on the long-term effect of L-dopa is at the core of the debate on how, if,and when to use dopamine agonists in the treatment of thedisease.2

Of special interest to us is the mechanism of receptor in-ternalization. Changes in the morphology and distribution ofbeta-adrenergic and muscarinic receptors have been demon-strated in rats exposed to chronic agonist treatment.3 Thesechanges may be induced by receptor-mediated activation ofphosphatidyl-N-monomethylethanolamine and phosphatidyl-choline methylation.4 Such a mechanism may be even moreimportant in Parkinson’s disease. Treatment with L-dopa de-pletes the methyl group’s donor S-adenosylmethionine in ratbrains and the cerebrospinal fluid of parkinsonian patients.5

The depletion of S-adenosylmethionine may therefore affectphospholipid methylation of the dopamine receptor and in-duce changes in receptor conformation and localization.3

Department of Neurology, Beth Israel Medical Center, AlbertEinstein College of Medicine, New York, NY

References1. Muriel MP, Bernard V, Levey AI, et al. Levodopa induces a cy-

toplasmic localization of D1 dopamine receptors in striatal neu-rons in Parkinson’s disease. Ann Neurol 1999;46:103–311

2. Olanow CW, Jenner P, Brooks D. Dopamine agonists and neu-roprotection in Parkinson’s disease. Ann Neurol 1998;44(Suppl1):S167–S174

3. Hirata F, Axelrod J. Phospholipid methylation and biological sig-nal transmission. Science 1980;209:1082–1090

4. Cimino M, Vantini G, Algeri S, et al. Age-related modificationof dopaminergic and beta-adrenergic receptor system: restorationto normal activity by modifying membrane fluidity withS-adenosylmethionine. Life Sci 1984;34:2029–2039

5. Surtees R, Hyland K. L-dihydroxyphenylalanine (levodopa) low-ers central nervous system S-adenosylmethionine concentrationsin humans. J Neurol Neurosurg Psychiatry 1990;53:569–572

LETTERS

136 Copyright © 2000 by the American Neurological Association

Reply

Marie-Paule Muriel, BS,* Veronique Bernard, PhD,†Allan I. Levey, MD, PhD,‡ Ouahiba Laribi, BS,†D. Nora Abrous, PhD,§ Yves Agid, MD, PhD,*Bertrand Bloch, MD, PhD,† andEtienne C. Hirsch, PhD*

We appreciate the opportunity given to us by Drs Di Roccoand Werner to amplify our description of dopamine receptorinternalization after agonist stimulation. Indeed, our studyreports for the first time an internalization of a neurotrans-mitter receptor in a neurodegenerative disease.1 Given previ-ous studies performed in the rat brain showing D1 receptorinternalization in the striatum after D1 dopamine agoniststimulation,2 such a phenomenon was also likely to occur inpatients with Parkinson’s disease treated with levodopa.Given that both the nigrostriatal lesion and the treatmentmay affect receptor localization in the parkinsonian striatum,it appeared necessary to determine the real origin of the in-ternalization. Our data obtained in rats with a nigral lesionclearly indicate that the internalization is not caused by thelesion. We chose to use a D1 selective agonist to simplify thedesign and interpretation of the results. Nevertheless, weagree with Drs Di Rocco and Werner that further studies areneeded to determine whether this phenomenon is also ob-served with other dopamine agonists specific for D1 or D2receptors or with levodopa. Furthermore, a dynamic studyover time would be all the more interesting to determinewhether such changes are associated with long-term loss oflevodopa efficacy or daily variation in levodopa effectiveness.Receptor trafficking is complex and involves acute eventsafter agonist stimulation (occurring within minutes) as wellas the effect of chronic treatment as discussed by Drs DiRocco and Werner. Given possible interference with othermedications, the difficulty in obtaining brains from patientswith Parkinson’s disease with a short postmortem delay toallow ultrastructural analysis, and the difficulty in control-ling for variations in drug plasma levels at the time ofdeath, such a study needs to be conducted in experimentalmodels of the disease.

From a more general point of view, receptor internaliza-tion is part of the complex physiological regulation of neu-rotransmission in vivo that occurs for various G protein–coupled receptors, including neuropeptide and acetylcho-line.3 There is now more and more evidence that receptorendocytosis and, more generally, receptor trafficking underthe control of neurotransmitter tone critically contribute toregulate the availability of receptors for endogenous ligandsor exogenous drugs.3 This strongly suggests that such eventsmay also be of particular importance in various diseases, in-cluding addiction.2–5 Furthermore, other biochemical eventsare likely to be involved in the smooth regulation of the neu-rotransmission. Receptor internalization may still be of par-ticular importance, because if the receptor is not present atthe plasma membrane of a given cell, it is unlikely that it willbe responsive to the neurotransmitter.

*Institut National de la Sante et de la Recherche MedicaleU289, Hopital de la Salpetriere, Paris, †Unite Mixte deRecherche Centre National de la Recherche Scientifique 5541,Laboratoire d’Histologie Embryologie and §Institut Nationalde la Sante et de la Recherche Medicale U279 InstitutFederatif de Recherche en Neurosciences cliniques etexperimentales, Universite Victor Segalen-Bordeaux, Bordeaux,France; and ‡Department of Neurology, Emory UniversitySchool of Medicine, Atlanta, GA

References1. Muriel MP, Bernard V, Levey A, et al. Levodopa induces a cy-

toplasmic localization of D1 dopamine receptors in striatal neu-rons in Parkinson’s disease. Ann Neurol 1999;46:103–111

2. Dumartin B, Caille I, Gonon F, Bloch B. Internalization of D1dopamine receptor in striatal neurons in vivo as evidence of ac-tivation by dopamine agonists. J Neurosci 1998;18:1650–1661

3. Bloch B, Dumartin B, Bernard V. In vivo regulation of intra-neuronal trafficking of G protein–coupled receptors for neuro-transmitters. TIPS 1999;20:315–319

4. Whistler JL, Chuang H-H, Chu P, et al. Functional dissociationof m-opioid receptor signaling and endocytosis: implications forthe biology of opiate tolerance and addiction. Neuron 1999;23:737–746

5. Roth BL, Willins DL. What’s all the rave about receptor inter-nalization. Neuron 1999;23:629–631

Cerebrospinal Fluid Interleukin-10 Levels inPrimary Central Nervous System Lymphoma:A Possible Marker of Response to Treatment?A. Salmaggi, MD, M. Eoli, MD, E. Corsini, BS,M. Gelati, BS, S. Frigerio, BS, A. Silvani, MD, andA. Boiardi, MD

Primary central nervous system lymphoma (PCNSL) is anon-Hodgkin’s lymphoma limited to the central nervous sys-tem (CNS); despite radiotherapy and chemotherapy, local re-currence is the rule.1

No biological markers predictive of outcome are availableto date, except for the recently reported Epstein-Barr virusDNA (EBV-DNA) concentration values in acquired immu-nodeficiency syndrome–related PCNSL.2

Previous studies have suggested a prognostically negativevalue of serum interleukin-10 (IL-10) concentration in sys-temic non-Hodgkin’s lymphoma3; more recently, elevatedcerebrospinal fluid (CSF) IL-10 levels have been detected inPCNSL involving the vitreous and with the presence of ma-lignant CSF cells.4 IL-10 enhances the proliferation of B cellsand their release of IgG; this activity may be relevant inB-cell phenotype malignancies such as PCNSL. Furthermore,IL-10 exhibits a strong DNA homology to the open readingframe in the EBV genome called BCRF-1.5

We tested CSF and serum IL-10 levels in 11 immunocom-petent B-cell PCNSL patients (6 male, 5 female; mean age, 52years; age range, 32–74 years) sampled mostly (7 patients)within the second chemotherapy cycle (M-BACOD, patients;HDMTX, 8 patients).

As controls, we investigated sera from 10 healthy subjects(4 male, 6 female; mean age, 31 years; age range, 25–45years). To assess the disease specificity of putative increases inCSF IL-10 concentrations, we also included 11 patients withother CNS tumors (4 with germinomas, 2 with teratocarci-

Annals of Neurology Vol 47 No 1 January 2000 137

noma, 2 with medulloblastoma, 1 with peripheral neuroec-todermal tumor, 1 with anaplastic astrocytoma, 1 with mel-anoma carcinomatosis) (2 female, 9 male; mean age, 27years; age range, 18–67 years) in whom CSF sampling waspart of diagnosis or therapy.

IL-10 quantitation was performed by a commerciallyavailable enzyme-linked immunosorbent assay kit (BioSourceInternational, Camarillo, CA).

Results are reported in Figure 1. Significantly higher CSFIL-10 levels were detected in PCNSL patients than in pa-tients with other CNS tumors (14.8 6 23 vs 0.23 6 0.26pg/ml, p , 0.01 by Mann-Whitney U test); serum IL-10levels were also slightly higher in PCNSL than in other CNStumors or in healthy controls.

In the 6 patients with CSF IL-10 levels higher than 9pg/ml, these levels were detected either concomitantly withor just prior to clinicoradiological worsening (within 1month). On the other hand, with the exception of 1 patient,all patients with CSF IL-10 levels lower than 5 pg/ml dis-played stable disease with a progression-free course rangingfrom 6 months to longer than 24 months. Only 1 patientdisplayed malignant cells in the CSF; this patient had ex-

tremely high CSF IL-10 levels (65 pg/ml) with radiologicallyevident disease dissemination.

Two findings are novel in our work. First, elevated CSFIL-10 levels were not strictly related to a finding of malig-nant lymphoma cells in the CSF, adding value to IL-10 mea-surement per se in PCNSL. Second, no control populationconsisting of patients with other CNS tumors with possibledissemination via the CSF or the presence of lymphocytes intheir tumors (such as germinomas) was included in Whitcupand co-worker’s study,4 making it impossible to draw con-clusions about the specificity of their findings. Moreover, nofollow-up data were reported relating CSF IL-10 levels tooutcome or response to treatments.

In our cohort, a good correlation was observed betweenCSF IL-10 levels and clinicoradiological evolution; individu-als with low CSF IL-10 concentrations displayed a good clin-ical course, whereas elevated CSF IL-10 was detected eithertogether with or shortly before disease evolution.

Because only a minority of immunocompetent PCNSLpatients displayed EBV-DNA in the CSF, IL-10 may have aprognostic value in those cases.

Neurological Institute C. Besta, Milan, Italy

References1. De Angelis LM, Yahalou J, Thaler HT, Kher V. Combined mo-

dality treatment for primary CNS lymphoma. J Clin Oncol1992;10:635–643

2. Antinori A, Cingolani A, De Luca A, et al. Epstein-Barr virus inmonitoring the response to therapy of acquired immunodefi-ciency syndrome–related primary central nervous system lym-phoma. Ann Neurol 1999;5:259–261

3. Blay JY, Burdin N, Rousset F, et al. Serum interleukin 10 innon-Hodgkin’s lymphoma: a prognostic factor. Blood 1993;82:2169–2174

4. Whitcup SM, Stark-Veancs V, Wittes RE, et al. Association ofinterleukin 10 in vitreous and cerebrospinal fluid and primarycentral nervous system lymphoma. Arch Ophthalmol 1997;115:1157–1160

5. Moore KW, Vieira P, Fiorentino DF, et al. Homology of cyto-kine synthesis inhibitory factor (IL-10) to the Epstein-Barr virusgene BCRF1. Science 1990;248:1230

Gene-Gene Interaction between Interleukin-6 anda2-Macroglobulin Influences the Risk forAlzheimer’s DiseaseMetin Bagli, PhD, Andreas Papassotiropoulos, MD,Frank Jessen, MD, Marie Luise Rao, PhD,Wolfgang Maier, MD, and Reinhard Heun, MD

Recently, we reported, in a case-control study with 102 Alz-heimer’s disease (AD) patients and 351 controls, that the Callele of a variable number tandem repeat polymorphism ofthe gene encoding the inflammatory cytokine interleukin-6(IL-6) was associated with a delayed initial onset of AD andreduced disease risk.1 This observation supports the notionthat inflammatory processes may contribute to AD-relatedneurodegeneration.

The steps of the inflammatory cascade and their relationto the pathological process of AD are not fully understood,but there are findings that demonstrate the participation ofIL-6 and the proteinase inhibitor a2-macroglobulin (a2M)

Fig 1. (A) Mean cerebrospinal fluid interleukin-10 (IL-10)levels in primary central nervous system lymphoma (PCNSL)and in other central nervous system (CNS) tumor patients.(B) Mean serum IL-10 levels in PCNSL, in other CNS tu-mor patients, and in healthy controls.

138 Annals of Neurology Vol 47 No 1 January 2000

in the cerebral immune response. It has been hypothesizedthat the neurodegenerative cascade starts with an altered IL-6–mediated synthesis of a2M and probably terminates withmodified b-amyloid deposition in neuritic plaques.2 A pen-tanucleotide deletion of the a2M gene (A2M) was recentlyfound to be associated with AD.3 However, our own results(unpublished data) and those of others failed to show an as-sociation between the A2M deletion and AD.4 The postulatedcommon pathway of IL-6 and a2M in the cerebral immuneresponse prompted us to examine the combined contributionof mutations of these genes to the susceptibility for AD.

We tested whether the reduced risk, previously observedfor AD in carriers of the IL-6 C allele, differed after strati-fication of the AD patients and controls according to theirA2M deletion genotype. Splitting the groups according totheir A2M deletion genotype showed that the decreased riskfor AD, in carriers of the C allele of the IL-6 gene, is solelydetectable among carriers of the A2M deletion but notamong noncarriers (Table). Thus, the protective effect of theC allele of the IL-6 gene is only apparent in the presence ofthe A2M deletion. The most critical factor that may give riseto spurious results in association studies is population strat-ification. As may be seen from the Table, genetic interactionsmay lead to different strata and different disease risks within

the same population. This type of population stratification,resulting from gene–gene interaction, may explain controver-sial results often observed in genetic association studies.

In conclusion, our results show that coexisting mutationsin the IL-6 and A2M genes influence the risk of AD viagene–gene interaction. This exemplifies the importance ofgene–gene interactions in the pathogenesis of geneticallycomplex diseases like AD.

Department of Psychiatry, University of Bonn, Bonn, Germany

References1. Papassotiropoulos A, Bagli M, Jessen F, et al. A genetic variation

of the inflammatory cytokine interleukin-6 delays the initial on-set and reduces the risk for sporadic Alzheimer’s disease. AnnNeurol 1999;45:666–668

2. Bauer J, Strauss S, Schreiter-Gasser U, et al. Interleukin-6 andalpha-2-macroglobulin indicate an acute-phase state in Alzhei-mer’s disease cortices. FEBS Lett 1991;285:111–114

3. Blacker D, Wilcox MA, Laird NM, et al. Alpha-2 macroglobulinis genetically associated with Alzheimer disease. Nat Genet 1998;19:357–360

4. Rogaeva EA, Premkumar S, Grubber J, et al. An alpha-2-macroglobulin insertion-deletion polymorphism in Alzheimerdisease. Nat Genet 1999;22:19–21

Table. Distribution of Interleukin-6 (IL-6) C Allele among Alzheimer’s Disease (AD) Patients and Controls in the Total Sampleand after Stratification According to the a2-Macroglobulin (A2M) Deletion Genotype

Total Sample

IL-6 C Allele AD Patients Controls

1 40 1822 62 169Odds ratio 0.60 (0.38–0.94)

A2M Deletion Carriers A2M Deletion Noncarriers

IL-6 C Allele AD Patients Controls IL-6 C Allele AD Patients Controls

1 8 57 1 32 1252 19 38 2 43 131Odds ratio 0.28 (0.11–0.71) Odds ratio 0.78 (0.46–1.31)

Data in parentheses represent the 95% confidence interval.

Annals of Neurology Vol 47 No 1 January 2000 139