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Is progressive multifocal leukoencephalopathy associated with intrathecal IgG synthesis?
Journal of Neuroimmunology, 10 (1985) 167-172 Elsevier
167
JNI 00322
Short C o m m u n i c a t i o n
Is Progressive Multifocal Leukoencephalopathy Associated with Intrathecal IgG Synthesis? P. Mazzarello, M. Poloni, M. Ceroni i and R. Scelsi 2 Clinica Neurologica I dell'Universith di Milano, Milan, t lstituto Neurologico dell'Universitgt di Pavia, and z Istituto di A natomia Patologica dell'Universith di Pavia, Pavia (Italy)
(Received 7 January, 1985) (Revised, received 10 June, 1985) (Accepted 10 June, 1985)
Summary Examination of the cerebrospinal fluid by isoelectric focusing was done in 2 cases of progressive multifocal leukoencephalopathy (PML). The diagnosis was confirmed at autopsy in one case. IgG oligoclonal bands were found in both, suggesting that there was intrathecal immunoglobulin synthesis. Production may be due to a specific intrathecal response to papova virus or to IgG oligoclonal formation by lymphoma cells confined to the central nervous system or to a specific immune response to tumor cell antigens. Key words: Progressive multifocal leukoencephalopathy - Cerebrospinal fluid - Isoelectric focusing - Oligoclonal bands
Introduction Progressive multifocal leukoencephalopathy (PML) is a rare disease of the central nervous system (CNS), usually occurring in patients with impairment of the immune system, e.g. Hodgkin's disease, myeloproliferative disorders or granulomatous disease (Walker 1978). PML has also been described recently in a patient with acquired immune deficiency syndrome (Bernick and Gregorios 1984). There is evidence that This work was supported by the Consiglio Nazionale per le Ricerche cdr. n. 83.02776.56 and 83.02068.04. Correspondence: P. Mazzarello, M.D., 1st Neurological Clinic, Settore Didattico, Ospedale S. Paolo, Via Di Rudini 8, I 20142 Milan, Italy. 0165-5728/85/$03.30 © 1985 Elsevier Science Publishers B.V. (Biomedical Division)
168 the CNS damage is due to an opportunistic infection with papova virus (Padgett et al. 1971) and the CSF is usually reported as normal (Walker 1978). We have observed 2 patients with malignant lymphoma and progressive neurological impairment highly suggestive of PML and have examined the CSF for IgG oligoclonal bands using isoelectric focusing.
Case Reports Case 1
M.P., a previously healthy 46-year-old male was admitted because of the insidious onset of mental changes and dysarthria. Clinical examination revealed hepatomegaly, mild splenomegaly, nystagmus, a confusional state and left pyramidal weakness. The EEG showed periods of delta rhythm and CT scan revealed conspicuous, diffuse cortical atrophy. Marrow aspiration was non-diagnostic. One month later the patient developed left hemiplegia and severe impairment of consciousness. A repeat CT examination showed low density areas in the white matter of both cerebral hemispheres, mainly in the periventricular regions. After a few days, he went into deep coma and developed quadriplegia with myoclonic jerks. Death occurred 40 days after admission. At necropsy, the cause of death was acute pulmonary congestion and edema by long-term congestive heart failure and bronchopneumonia. There was generalized mild lymph node enlargement and histological examination revealed a malignant non-Hodgkin's lymphoma. Examination of the CNS showed multifocal, large and small, round or oval patches of demyelination, distributed in the cortex, at the corticomedullary junction, in the white matter of the cerebrum and in the cerebellar hemispheres. Border areas between lesions, and normal tissue, were infiltrated by lymphocytes, macrophages; numerous polymorphous and bizarre astrocytes and oligodendrocytes with hyperchromatic and prominent nuclei were seen. In the remaining areas no inflammatory response was evident. Case 2
B.V., a 73-year-old male presented with weight loss, depression and insomnia. On admission he had hepatomegaly and axillary and inguinal lymphadenopathy. Clinical and E M G examination showed a mild polyneuropathy which was followed in a few days by the appearance of bilateral pyramidal signs. At the same time, parietal and occipital theta waves and sharp-waves were seen on EEG examination. CT scan showed severe superficial and deep cerebral atrophy. Biopsy of an inguinal lymph node revealed a malignant lymphoma of lymphocytic type (Kiel classification, Gerard-Marchant 1974). 20 days after admission, the patient's condition deteriorated with the appearance of cortical blindness and myoclonic jerks, predominantly in the lower limbs. After 30 days a confusional state appeared and was followed by a deep coma which led to his death 45 days after admission. Permission for an autopsy was not granted.
169 Materials and Methods
In addition to routine CSF examination, CSF and serum IgG and albumin levels were evaluated by an immunonephelometric technique (Beckman analyzer); the serum/CSF albumin quotient (Schliep and Felgenhauer 1978), the IgG index (Link 1975; Link and Tibbling 1977) and the intrathecal IgG synthesis (Tourtellotte and Ma 1978) were calculated to measure the blood-brain barrier permeability and any intrathecal IgG production. Before IEF, the CSF was concentrated 20 times by ultrafiltration (Minicon CS 15, Amicon, Oosterhout, The Netherlands) and the serum samples were diluted 10 times with distilled water. Isoelectric focusing examination in thin layer polyacrylamide gel was carried out over a pH range 3.5-9.5, using Ampholine PAG plates (LKB, Bromma, Sweden), as previously described (Poloni et al. 1979). Immunofixation was performed after IEF, using monospecific antiserum directed against human IgG gamma chains (Dakopatts, Denmark) as previously described (Rocchelli et al. 1981).
Results
CSF and serum were examined twice (at admission and one month later, a few days before death) in the first case'and once in the second. Several oligoclonal bands were observed in the CSF but not in the serum, at the same pH, both in case 1 (first and second examination) and in case 2 (Fig. 1). The cell counts, albumin and IgG concentrations, serum/CSF albumin quotients, IgG index and IgG synthesis are summarized in Table 1. The oligoclonal fractions were identified by immunofixation and in both cases were proved to be IgG.
Discussion
The CSF is usually reported as normal in PML (Walker 1978) but it has not been carefully studied using IEF until now. No oligoclonal IgG band on agarose gel electrophoresis was demonstrated in the patient reported by Johnson et al. (1980), in their extensive study of the CSF in multiple sclerosis and other neurological diseases. Both the patients described here displayed oligoclonal IgG bands in their CSF, without similar findings in the serum. The IgG index and the IgG synthesis were slightly elevated only in one case. These facts indicate the presence of a mild intrathecal immune response in PML. A similar result has been briefly reported recently, in 1 of 2 affected cases, by Alemh et al. (1984). CSF oligoclonal bands are found in multiple sclerosis and in several infectious diseases of the CNS: subacute sclerosing panencephalitis, post-rubeola panencephalitis, lues cerebri, tuberculous meningitis (Vandvik and Skrede 1973; Laurenzi and Link 1978; Kinnman et al. 1981). In the latter conditions, they represent a specific intrathecal immune response against the infectious agent (Wolinsky et al.
170
Fig. 1. C S F s a m p l e s e x h i b i t i n g o l i g o c l o n a l I g G b a n d s ( a r r o w s ) n o t r e f e r a b l e to s e r u m c h a n g e s . S e r u m s a m p l e s f r o m the s a m e p a t i e n t o n the right. A : case 1, B: case 2. T h e a n o d e is at the top. TABLE 1 CSF FINDINGS
IN T H E P A T I E N T S E X A M I N E D Cell c o u n t nv a < 3 mm 3
Albumin nv < 27 mg/dl
IgG nv < 4 mg/dl
Serum/CSF albumin nv > 130
IgG index nv < 0.69
Case 1 (First e x a m i n a t i o n )
0.5
24.4
6.66
115
0.72
Case 1 (Second examination)
0.1
34
9.4
66
0.47
- 1
Case 2
0.8
33.2
7.98
94
0.40
- 20.8
a n v = n o r m a l values (mean_+ S D ) for o u r l a b o r a t o r y .
IgG synthesis nv < 3.0 mg/day 8.9
171 1976; Nordal et al. 1978; K i n n m a n et al. 1981; Shorr et al. 1981; Vartdal et al. 1982). The presence of oligoclonal I g G bands has also been observed in cases of Burkitt's l y m p h o m a with C N S involvement; here an immune reaction against the Epstein-Barr virus or a non-specific activation of i m m u n e cells by the virus have been suggested (Wallen et al. 1983). The oligoclonal bands in P M L might be thought to be an immune response against papova virus, the infectious agent (Padgett et al. 1971) associated with this disease. High titers against JCV or SV 40 (2 papova viruses associated with P M L ) in serum are reported in a few cases of P M L (Weiner et al. 1972; Bauer et al. 1973). Nevertheless an immune reaction is difficult to explain in P M L which usually develops against a background of immune deficiency. Intrathecal I g G synthesis m a y however be preserved when there is systemic immunodeficiency, as has been shown in some cases of progressive neurological involvement associated with late-onset immunodeficiency (Lord et al. 1973; Rocchelli et al. 1982). Alternative possibilities are those of IgG oligoclonal production by l y m p h o m a cells confined to the C N S or a specific immune response to tumor cell antigens. The first hypothesis is unlikely because the presence of a generalized disease should lead to the appearance of I g G bands in both CSF and serum. The other abnormal finding in these cases was mild permeability of the b l o o d - b r a i n barrier, which became more severe towards death in one case. This is not surprising, bearing in mind the abnormal hypodense white substance at CT. In conclusion, CSF examination of suspected cases of P M L m a y be useful; more cases are needed to define the frequency of the abnormalities detected, their specificity and the nature of the antigens against which the oligoclonal bands are directed.
Acknowledgement We thank Mrs. Iliana Copez for secretarial assistance.
References Alemh, G., N. Carducci, N. Felici, S. Galgani, R. Giannuzzi, G. Piazza, T. Visca, G. Visco and T. Faraggiana, Two cases of progressive multifocal leukoencephalopathy, Acta Neurol., 6 (1984) 375. Bauer, W.R., A.P. Turel Jr. and K.P. Johnson, Progressive multifocal leukoencephalopathy and cytarabine, J. Am. Med. Assoc., 226 (1973) 174-176. Bernick, C. and J.B. Gregorios, Progressive multifocal leukoencephalopathy in a patient with acquired immuno deficiency syndrome, Arch. Neurol., 41 (1984) 780-782. Gerard-Marchant, R., I. Hamlin, K. Lennert, F. Rilke, A.G. Stansfeld and J.A.M. van Unnik, Lancet, ii (August 17) (1974). Johnson, K.P., W.H. Likosky, B.J. Nelson and G. Fein, Comprehensive viral immunology of multiple sclerosis. I. Clinical, epidemiological and CSF studies, Arch. Neurol., 37 (1980) 537-541. Kinnman, J., H. Link and A. Fryd6n, Characterization of antibody activity in oligoclonal IgG synthesized within the central nervous system in a patient with tuberculous meningitis, J. Clin. Microbiol., 13 (1981) 30-35.
172 Laurenzi, M.A. and H. Link, Comparison between agarose gel electrophoresis and isoelectric focusing of CSF for demonstration of oligoclonal immunoglobulin bands in neurological disorders, Acta Neurol. Scand., 58 (1978) 148-156. Link, H., The value of cerebrospinal fluid analysis in clinical neurology, Proc. XIX National Congress of Neurology, Genova, Italy, 1975. Link, H. and G. Tibbling, Principles of albumin and lgG analyses in neurological disorders. Ill. Evaluation of lgG synthesis within the central nervous system in multiple sclerosis, Scand. J. Clin. Lab. Invest., 37 (1977) 397-401. Lord, R.A., R.M. Goldelum, P.M. Forman, E. Dupree, W.D. Storey and A.S. Goldman, Cerebrospinalfluid IgM in the absence of serum IgM in combined immunodeficiency, Lancet, 8 (1973) 528-529. Nordal, H.J., B. Vandvik and E. Norrby, Demonstration of electrophoretically restricted virus-specific antibodies in serum and cerebrospinal fluid by imprint electroimmunofixation, Scand. J. Immunol., 7 (1978) 381-388. Padgett, B.L., D.L. Walker, G.M. Zurhein, R.J. Eckroade and B.H. Dessel, Cultivation of papova-like virus from human brain with progressive multifocal leukoencephalopathy, Lancet i (1971) 1257-1260. Poloni, M., B. Rocchelli, R. Scelsi and P. Pinelli, lntrathecal IgG synthesis in multiple sclerosis and other neurological diseases. A comparative evaluation by IgG-Index and isoelectric focusing, J. Neurol., 221 (1979) 245-255. Rocchelli, B., M. Poloni, P. Mazzarello and M.L. Delodovici, Identification of the • and ~ light chains within the CSF immunoglobulin region in multiple sclerosis and subacute sclerosing panencephalitis by immunofixation after isoelectric focusing, J. Neurol., 226 (1981) 169-179. Rocchelli, B., G.L. Marseglia, P. Mazzarello, M. Duse, M. Poloni and A.G. Ugazio, Intrathecal synthesis of immunoglobulin light chains in a child with late-onset agammaglobulinemia, J. Neuroimmunol., 2 (1982) 277-281. Schliep, G. and K. Felgenhauer, Serum-CSF protein gradients, the blood-CSF barrier and the local immuno response, J. Neurol., 218 (1978) 77-96. Shorr, J., B. RostrOm and H. Link, Antibodies to viral and nonviral antigens in subacute sclerosing panencephalitis and multiple sclerosis demonstrated by thin-layer polyacrylamide gel isoelectric focusing, antigen immunofixation and autoradiography, J. Neurol. Sci., 49 (1981) 99-108. Tourtellotte, W.W. and B.I. Ma, Multiple sclerosis: The blood-brain barrier and the measurement of de novo central nervous system IgG synthesis, Neurology (Minneap.), 28 (1978) 76-83. Vandvik, B. and S. Skrede, Electrophoretic examination of cerebrospinal fluid proteins in multiple sclerosis and other neurological diseases, Eur. Neurol., 9 (1973) 224-241. Vartdal, F., B. Vandvik, T.E. Michaelsen, K. Loe and E. Norrby, Neurosyphilis: lntrathecal synthesis of oligoclonal antibodies to Treponema pallidum, Ann. Neurol., 11 (1982) 35-40. Walker, D.L., Progressive multifocal leukoencephalopathy, an opportunistic viral infection of the central nervous system. In: P.J. Vinken and G.W. Bruyn (Eds.), Handbook of Clinical Neurology, Vol. 34, Elsevier/North-Holland, Amsterdam, 1978, pp. 307 329. Wallen, W.C., R.J. Biggar, P.M. Levine and M.V. Iivanainen, Oligoclonal IgG in CSF of patients with African Burkitt's lymphoma, Arch. Neurol., 40 (1983) 11-13. Weiner, L.P., R.M. Herndon, O.N. Norayan, R.T. Johnson, K. Shah, L.J. Rubinstein, T.J. Preziosi and F.K. Conley, Isolation of virus related to SV 40 from patients with progressive multifocal leukoencephalopathy, N. Engl. J. Med., 286 (1972) 385-390. Wolinsky, J.S., B.O. Berg and C.J. Maitland, Progressive rubella panencephalitis, Arch. Neurol., 33 (1976) 722-723.
167
JNI 00322
Short C o m m u n i c a t i o n
Is Progressive Multifocal Leukoencephalopathy Associated with Intrathecal IgG Synthesis? P. Mazzarello, M. Poloni, M. Ceroni i and R. Scelsi 2 Clinica Neurologica I dell'Universith di Milano, Milan, t lstituto Neurologico dell'Universitgt di Pavia, and z Istituto di A natomia Patologica dell'Universith di Pavia, Pavia (Italy)
(Received 7 January, 1985) (Revised, received 10 June, 1985) (Accepted 10 June, 1985)
Summary Examination of the cerebrospinal fluid by isoelectric focusing was done in 2 cases of progressive multifocal leukoencephalopathy (PML). The diagnosis was confirmed at autopsy in one case. IgG oligoclonal bands were found in both, suggesting that there was intrathecal immunoglobulin synthesis. Production may be due to a specific intrathecal response to papova virus or to IgG oligoclonal formation by lymphoma cells confined to the central nervous system or to a specific immune response to tumor cell antigens. Key words: Progressive multifocal leukoencephalopathy - Cerebrospinal fluid - Isoelectric focusing - Oligoclonal bands
Introduction Progressive multifocal leukoencephalopathy (PML) is a rare disease of the central nervous system (CNS), usually occurring in patients with impairment of the immune system, e.g. Hodgkin's disease, myeloproliferative disorders or granulomatous disease (Walker 1978). PML has also been described recently in a patient with acquired immune deficiency syndrome (Bernick and Gregorios 1984). There is evidence that This work was supported by the Consiglio Nazionale per le Ricerche cdr. n. 83.02776.56 and 83.02068.04. Correspondence: P. Mazzarello, M.D., 1st Neurological Clinic, Settore Didattico, Ospedale S. Paolo, Via Di Rudini 8, I 20142 Milan, Italy. 0165-5728/85/$03.30 © 1985 Elsevier Science Publishers B.V. (Biomedical Division)
168 the CNS damage is due to an opportunistic infection with papova virus (Padgett et al. 1971) and the CSF is usually reported as normal (Walker 1978). We have observed 2 patients with malignant lymphoma and progressive neurological impairment highly suggestive of PML and have examined the CSF for IgG oligoclonal bands using isoelectric focusing.
Case Reports Case 1
M.P., a previously healthy 46-year-old male was admitted because of the insidious onset of mental changes and dysarthria. Clinical examination revealed hepatomegaly, mild splenomegaly, nystagmus, a confusional state and left pyramidal weakness. The EEG showed periods of delta rhythm and CT scan revealed conspicuous, diffuse cortical atrophy. Marrow aspiration was non-diagnostic. One month later the patient developed left hemiplegia and severe impairment of consciousness. A repeat CT examination showed low density areas in the white matter of both cerebral hemispheres, mainly in the periventricular regions. After a few days, he went into deep coma and developed quadriplegia with myoclonic jerks. Death occurred 40 days after admission. At necropsy, the cause of death was acute pulmonary congestion and edema by long-term congestive heart failure and bronchopneumonia. There was generalized mild lymph node enlargement and histological examination revealed a malignant non-Hodgkin's lymphoma. Examination of the CNS showed multifocal, large and small, round or oval patches of demyelination, distributed in the cortex, at the corticomedullary junction, in the white matter of the cerebrum and in the cerebellar hemispheres. Border areas between lesions, and normal tissue, were infiltrated by lymphocytes, macrophages; numerous polymorphous and bizarre astrocytes and oligodendrocytes with hyperchromatic and prominent nuclei were seen. In the remaining areas no inflammatory response was evident. Case 2
B.V., a 73-year-old male presented with weight loss, depression and insomnia. On admission he had hepatomegaly and axillary and inguinal lymphadenopathy. Clinical and E M G examination showed a mild polyneuropathy which was followed in a few days by the appearance of bilateral pyramidal signs. At the same time, parietal and occipital theta waves and sharp-waves were seen on EEG examination. CT scan showed severe superficial and deep cerebral atrophy. Biopsy of an inguinal lymph node revealed a malignant lymphoma of lymphocytic type (Kiel classification, Gerard-Marchant 1974). 20 days after admission, the patient's condition deteriorated with the appearance of cortical blindness and myoclonic jerks, predominantly in the lower limbs. After 30 days a confusional state appeared and was followed by a deep coma which led to his death 45 days after admission. Permission for an autopsy was not granted.
169 Materials and Methods
In addition to routine CSF examination, CSF and serum IgG and albumin levels were evaluated by an immunonephelometric technique (Beckman analyzer); the serum/CSF albumin quotient (Schliep and Felgenhauer 1978), the IgG index (Link 1975; Link and Tibbling 1977) and the intrathecal IgG synthesis (Tourtellotte and Ma 1978) were calculated to measure the blood-brain barrier permeability and any intrathecal IgG production. Before IEF, the CSF was concentrated 20 times by ultrafiltration (Minicon CS 15, Amicon, Oosterhout, The Netherlands) and the serum samples were diluted 10 times with distilled water. Isoelectric focusing examination in thin layer polyacrylamide gel was carried out over a pH range 3.5-9.5, using Ampholine PAG plates (LKB, Bromma, Sweden), as previously described (Poloni et al. 1979). Immunofixation was performed after IEF, using monospecific antiserum directed against human IgG gamma chains (Dakopatts, Denmark) as previously described (Rocchelli et al. 1981).
Results
CSF and serum were examined twice (at admission and one month later, a few days before death) in the first case'and once in the second. Several oligoclonal bands were observed in the CSF but not in the serum, at the same pH, both in case 1 (first and second examination) and in case 2 (Fig. 1). The cell counts, albumin and IgG concentrations, serum/CSF albumin quotients, IgG index and IgG synthesis are summarized in Table 1. The oligoclonal fractions were identified by immunofixation and in both cases were proved to be IgG.
Discussion
The CSF is usually reported as normal in PML (Walker 1978) but it has not been carefully studied using IEF until now. No oligoclonal IgG band on agarose gel electrophoresis was demonstrated in the patient reported by Johnson et al. (1980), in their extensive study of the CSF in multiple sclerosis and other neurological diseases. Both the patients described here displayed oligoclonal IgG bands in their CSF, without similar findings in the serum. The IgG index and the IgG synthesis were slightly elevated only in one case. These facts indicate the presence of a mild intrathecal immune response in PML. A similar result has been briefly reported recently, in 1 of 2 affected cases, by Alemh et al. (1984). CSF oligoclonal bands are found in multiple sclerosis and in several infectious diseases of the CNS: subacute sclerosing panencephalitis, post-rubeola panencephalitis, lues cerebri, tuberculous meningitis (Vandvik and Skrede 1973; Laurenzi and Link 1978; Kinnman et al. 1981). In the latter conditions, they represent a specific intrathecal immune response against the infectious agent (Wolinsky et al.
170
Fig. 1. C S F s a m p l e s e x h i b i t i n g o l i g o c l o n a l I g G b a n d s ( a r r o w s ) n o t r e f e r a b l e to s e r u m c h a n g e s . S e r u m s a m p l e s f r o m the s a m e p a t i e n t o n the right. A : case 1, B: case 2. T h e a n o d e is at the top. TABLE 1 CSF FINDINGS
IN T H E P A T I E N T S E X A M I N E D Cell c o u n t nv a < 3 mm 3
Albumin nv < 27 mg/dl
IgG nv < 4 mg/dl
Serum/CSF albumin nv > 130
IgG index nv < 0.69
Case 1 (First e x a m i n a t i o n )
0.5
24.4
6.66
115
0.72
Case 1 (Second examination)
0.1
34
9.4
66
0.47
- 1
Case 2
0.8
33.2
7.98
94
0.40
- 20.8
a n v = n o r m a l values (mean_+ S D ) for o u r l a b o r a t o r y .
IgG synthesis nv < 3.0 mg/day 8.9
171 1976; Nordal et al. 1978; K i n n m a n et al. 1981; Shorr et al. 1981; Vartdal et al. 1982). The presence of oligoclonal I g G bands has also been observed in cases of Burkitt's l y m p h o m a with C N S involvement; here an immune reaction against the Epstein-Barr virus or a non-specific activation of i m m u n e cells by the virus have been suggested (Wallen et al. 1983). The oligoclonal bands in P M L might be thought to be an immune response against papova virus, the infectious agent (Padgett et al. 1971) associated with this disease. High titers against JCV or SV 40 (2 papova viruses associated with P M L ) in serum are reported in a few cases of P M L (Weiner et al. 1972; Bauer et al. 1973). Nevertheless an immune reaction is difficult to explain in P M L which usually develops against a background of immune deficiency. Intrathecal I g G synthesis m a y however be preserved when there is systemic immunodeficiency, as has been shown in some cases of progressive neurological involvement associated with late-onset immunodeficiency (Lord et al. 1973; Rocchelli et al. 1982). Alternative possibilities are those of IgG oligoclonal production by l y m p h o m a cells confined to the C N S or a specific immune response to tumor cell antigens. The first hypothesis is unlikely because the presence of a generalized disease should lead to the appearance of I g G bands in both CSF and serum. The other abnormal finding in these cases was mild permeability of the b l o o d - b r a i n barrier, which became more severe towards death in one case. This is not surprising, bearing in mind the abnormal hypodense white substance at CT. In conclusion, CSF examination of suspected cases of P M L m a y be useful; more cases are needed to define the frequency of the abnormalities detected, their specificity and the nature of the antigens against which the oligoclonal bands are directed.
Acknowledgement We thank Mrs. Iliana Copez for secretarial assistance.
References Alemh, G., N. Carducci, N. Felici, S. Galgani, R. Giannuzzi, G. Piazza, T. Visca, G. Visco and T. Faraggiana, Two cases of progressive multifocal leukoencephalopathy, Acta Neurol., 6 (1984) 375. Bauer, W.R., A.P. Turel Jr. and K.P. Johnson, Progressive multifocal leukoencephalopathy and cytarabine, J. Am. Med. Assoc., 226 (1973) 174-176. Bernick, C. and J.B. Gregorios, Progressive multifocal leukoencephalopathy in a patient with acquired immuno deficiency syndrome, Arch. Neurol., 41 (1984) 780-782. Gerard-Marchant, R., I. Hamlin, K. Lennert, F. Rilke, A.G. Stansfeld and J.A.M. van Unnik, Lancet, ii (August 17) (1974). Johnson, K.P., W.H. Likosky, B.J. Nelson and G. Fein, Comprehensive viral immunology of multiple sclerosis. I. Clinical, epidemiological and CSF studies, Arch. Neurol., 37 (1980) 537-541. Kinnman, J., H. Link and A. Fryd6n, Characterization of antibody activity in oligoclonal IgG synthesized within the central nervous system in a patient with tuberculous meningitis, J. Clin. Microbiol., 13 (1981) 30-35.
172 Laurenzi, M.A. and H. Link, Comparison between agarose gel electrophoresis and isoelectric focusing of CSF for demonstration of oligoclonal immunoglobulin bands in neurological disorders, Acta Neurol. Scand., 58 (1978) 148-156. Link, H., The value of cerebrospinal fluid analysis in clinical neurology, Proc. XIX National Congress of Neurology, Genova, Italy, 1975. Link, H. and G. Tibbling, Principles of albumin and lgG analyses in neurological disorders. Ill. Evaluation of lgG synthesis within the central nervous system in multiple sclerosis, Scand. J. Clin. Lab. Invest., 37 (1977) 397-401. Lord, R.A., R.M. Goldelum, P.M. Forman, E. Dupree, W.D. Storey and A.S. Goldman, Cerebrospinalfluid IgM in the absence of serum IgM in combined immunodeficiency, Lancet, 8 (1973) 528-529. Nordal, H.J., B. Vandvik and E. Norrby, Demonstration of electrophoretically restricted virus-specific antibodies in serum and cerebrospinal fluid by imprint electroimmunofixation, Scand. J. Immunol., 7 (1978) 381-388. Padgett, B.L., D.L. Walker, G.M. Zurhein, R.J. Eckroade and B.H. Dessel, Cultivation of papova-like virus from human brain with progressive multifocal leukoencephalopathy, Lancet i (1971) 1257-1260. Poloni, M., B. Rocchelli, R. Scelsi and P. Pinelli, lntrathecal IgG synthesis in multiple sclerosis and other neurological diseases. A comparative evaluation by IgG-Index and isoelectric focusing, J. Neurol., 221 (1979) 245-255. Rocchelli, B., M. Poloni, P. Mazzarello and M.L. Delodovici, Identification of the • and ~ light chains within the CSF immunoglobulin region in multiple sclerosis and subacute sclerosing panencephalitis by immunofixation after isoelectric focusing, J. Neurol., 226 (1981) 169-179. Rocchelli, B., G.L. Marseglia, P. Mazzarello, M. Duse, M. Poloni and A.G. Ugazio, Intrathecal synthesis of immunoglobulin light chains in a child with late-onset agammaglobulinemia, J. Neuroimmunol., 2 (1982) 277-281. Schliep, G. and K. Felgenhauer, Serum-CSF protein gradients, the blood-CSF barrier and the local immuno response, J. Neurol., 218 (1978) 77-96. Shorr, J., B. RostrOm and H. Link, Antibodies to viral and nonviral antigens in subacute sclerosing panencephalitis and multiple sclerosis demonstrated by thin-layer polyacrylamide gel isoelectric focusing, antigen immunofixation and autoradiography, J. Neurol. Sci., 49 (1981) 99-108. Tourtellotte, W.W. and B.I. Ma, Multiple sclerosis: The blood-brain barrier and the measurement of de novo central nervous system IgG synthesis, Neurology (Minneap.), 28 (1978) 76-83. Vandvik, B. and S. Skrede, Electrophoretic examination of cerebrospinal fluid proteins in multiple sclerosis and other neurological diseases, Eur. Neurol., 9 (1973) 224-241. Vartdal, F., B. Vandvik, T.E. Michaelsen, K. Loe and E. Norrby, Neurosyphilis: lntrathecal synthesis of oligoclonal antibodies to Treponema pallidum, Ann. Neurol., 11 (1982) 35-40. Walker, D.L., Progressive multifocal leukoencephalopathy, an opportunistic viral infection of the central nervous system. In: P.J. Vinken and G.W. Bruyn (Eds.), Handbook of Clinical Neurology, Vol. 34, Elsevier/North-Holland, Amsterdam, 1978, pp. 307 329. Wallen, W.C., R.J. Biggar, P.M. Levine and M.V. Iivanainen, Oligoclonal IgG in CSF of patients with African Burkitt's lymphoma, Arch. Neurol., 40 (1983) 11-13. Weiner, L.P., R.M. Herndon, O.N. Norayan, R.T. Johnson, K. Shah, L.J. Rubinstein, T.J. Preziosi and F.K. Conley, Isolation of virus related to SV 40 from patients with progressive multifocal leukoencephalopathy, N. Engl. J. Med., 286 (1972) 385-390. Wolinsky, J.S., B.O. Berg and C.J. Maitland, Progressive rubella panencephalitis, Arch. Neurol., 33 (1976) 722-723.