The significance of abnormal immune responses in patients with multiple sclerosis

An extended association screen in multiple sclerosis using 202 microsatellite markers targeting apoptosis-related genes does not reveal new predisposing factors

Apoptosis, the programmed death of cells, plays a distinct role in the etiopathogenesis of Multiple sclerosis (MS), a common disease of the central nervous system with complex genetic background. Yet, it is not clear whether the impact of apoptosis is due to altered apoptotic behaviour caused by variations of apoptosis-related genes. Instead, apoptosis in MS may also represent a secondary response to cellular stress during acute inflammation in the central nervous system. Here, we screened 202 apoptosis-related genes for association by genotyping 202 microsatellite markers in initially 160 MS patients and 160 controls, both divided in 4 sets of pooled DNA samples, respectively. When applying Bonferroni correction, no significant differences in allele frequencies were detected between MS patients and controls. Nevertheless, we chose 7 markers for retyping in individual DNA samples, thereby eliminating 6 markers from the list of candidates. The remaining candidate, the ERBB3 gene microsatellite, was genotyped in additional 245 MS patients and controls. No association of the ERBB3 marker with the disease was detected in these additional cohorts. In consequence, we did not find further evidence for apoptosis-related genes as predisposition factors in MS.

Intrathecal IgG synthesis: marker of progression in multiple sclerosis patients

OBJECTIVES

We study the power of IgG synthesis value as a marker of disease activity in multiple sclerosis (MS).

MATERIAL AND METHODS

Link index was calculated in 202 MS patients. Time between first, second and third attack and progression index (PI) were compared in patient with normal (NLI) high (HL) or very high Link index (VHLI).

RESULTS

Secondary progressive (SP) patients had a higher LI than relapsing-remitting (RR) and primary progressive (PP) courses (1.10 +/- 0.5 for SP vs 0.86 +/- 0.5 for RR and 0.81 +/- 0.5 for PP, P=0.01 and 0.03, respectively). Having a HLI in MS RR and SP patients has no time effect in the development of the second and third attack. PI was higher in patients with VHIL (0.67 +/- 0.7) vs patients with NLI (0.42 +/- 0.4, P=0.008) and with HLI (0.39 +/- 0.3, P=0.001).

CONCLUSIONS

This study confirmed that LI is a good marker of subsequent progression of MS.

Myelin basic protein-specific T lymphocytes in multiple sclerosis and controls: precursor frequency, fine specificity, and cytotoxicity

A panel of 90 myelin basic protein (MBP)-specific T-cell lines were derived from peripheral blood of eight patients with multiple sclerosis and four normal subjects. The precursor frequency of MBP-reactive T cells in peripheral blood mononuclear cells ranged from 10(-7) to 9 x 10(-7) (mean, 6.7 x 10(-7)) in the group of patients with multiple sclerosis and from 0.5 x 10(-7) to 9.8 x 10(-7) (mean, 5.6 x 10(-7)) in the control subjects. This difference between the two groups was not statistically significant (p greater than 0.1). These T-cell lines expressed exclusively CD3+CD4+CD8- phenotypes and were restricted predominantly by HLA-DR molecules. When tested with fragments and synthetic peptides of human MBP, these MBP-specific T-cell lines (45 lines for each group) displayed a limited heterogeneous pattern with a biased recognition to peptide 84-102 and the C-terminal peptide 149-171. The reactivity to the 84-102 region of MBP was associated with the HLA-DR2, DRw15 (DRw15,2) haplotype, whereas the recognition to peptide 149-171 did not correlate with a particular HLA-DR allele(s). Furthermore, the majority of T-cell lines (greater than 75%) were found to exhibit substantial cytotoxic activity against MBP-coated target cells, but showing no significant difference between these two groups. This MBP-dependent cytotoxicity was not associated with epitope specificities of the T-cell lines tested.

Preferential peptide specificity and HLA restriction of myelin basic protein-specific T cell clones derived from MS patients

A panel of 17 myelin basic protein (MBP)-specific T lymphocyte clones were generated from four multiple sclerosis (MS) patients. All T cell clones expressed CD4 phenotype and 14 clones exhibited substantial cytotoxic activity on MBP-coated target cells. T cell recognition sites of the clones on human MBP were identified by using MBP fragments and synthetic peptides. Despite the fact that at least three epitopes were defined, these T cell clones displayed a striking bias to the C-terminal peptide 149-171 independent of differences in HLA-DR and DQ expression. In addition, the T cell responses of the clones appeared to be restricted by HLA-DR molecules irrespective of peptide specificities. The present study suggests an immunodominant property of the C-terminal peptide for HLA-DR-restricted T cell responses to MBP. However, its association with encephalitogenicity in humans and its potential pathologic importance in MS await further clarification.

Human myelin basic protein-specific cytolytic T lymphocyte clones are functionally restricted by HLA class II gene products

Cellular immune reactions against the autoantigen myelin basic protein (MBP) are strongly implicated in the occurrence of postinfectious and postvaccination encephalomyelitis. Clinical autoimmune encephalomyelitis in experimental animals can be transferred with cloned MBP-specific cytolytic major histocompatibility complex Class II-restricted T lymphocytes. The HLA restriction pattern of specific proliferative and cytolytic functions of two human MBP-specific cytotoxic T lymphocyte clones, derived from two different multiple sclerosis patients, was analyzed in detail. Using monoclonal antibodies against various HLA gene products and allogeneic Epstein-Barr virus-transformed B cells as antigen-presenting cells and as targets for cytolysis, it was found that MBP-specific functions of the T cell clones was restricted by HLA class II antigens, and, more specifically, by molecules encoded for by DR locus genes.

In vitro functional blocking of myelin basic protein-specific cytolytic human T lymphocyte clones by immunosuppressive drugs and monoclonal antibodies

The in vitro effects of cyclosporin A, prednisolone, and anti-CD4 monoclonal antibody WW.T4 on myelin basic protein-specific human CD4+ cytolytic T lymphocyte clones were studied. Functional assays of antigen-specific proliferation, induction of specific lysis, cytolysis itself, and interferon-gamma production were done. Prednisolone decreased secretion of interferon-gamma by the clones and blocked specific proliferation; the latter could, however, be overcome by the addition of exogenous interleukin 2. It did not influence cytolytic properties. In contrast, cyclosporin A and WW.T4 blocked the four antigen-specific functions of the autoimmune myelin basic protein-specific human T cell clones measured.

Multiple sclerosis intra-blood-brain-barrier IgG synthesis: effect of pulse intravenous and intrathecal corticosteroids

Nine severely disabled clinically definite chronic progressive multiple sclerosis (MS) patients who had at least one determination of intra-blood-brain-barrier (BBB) IgG synthesis rate of greater than 7 mg/day (upper limit of normal = 3.3) participated in this study. Seven patients were given 1 gram of methylprednisolone sodium succinate (MP) by intravenous infusion over 30 minutes once a day for 3 days. Statistically significant (p less than .05) reduction in intra-BBB IgG synthesis (mg/day) was seen in 4/7 patients, but in only 2 were normal levels of synthesis rate (less than 3.3 mg/day) attained. Rebound of IgG synthesis to premedication rates occurred within 30 days in 2/4 patients. There was no change in intensity or pattern of cerebrospinal fluid (CSF) oligoclonal IgG bands by isoelectric focusing, immunofixation, and silver staining. A subsequent course of intrathecal methylprednisolone acetate (MPA) (80 mg twice a week for 5 weeks) was given to 5 of the 7 patients and to 2 additional patients not previously treated. In spite of signs of subarachnoid inflammation, a statistically significant depression of intra-BB synthesis, which far exceeded that from the pulse treatment occurred in all 7, including the 2 patients whose intra-BBB IgG synthesis rates were previously resistant to pulse steroid administration. Normal levels of synthesis were rapidly reached in 4/7 patients; however, an IgG synthesis rebound occurred in 3/7 patients which was just as rapid. One out of 7 patients showed a temporary reduction in the number of cathodic IgG oligoclonal bands in the CSF. Two patients required discontinuation of treatment due to aseptic meningitis in one and progressive weakness in the other. Clinically, these severely afflicted patients with fixed deficits remained unchanged with either treatment protocol. While MPA and ACTH have similar initial effect on the central nervous systems (CNS) inflammatory response in MS, the well documented risk of serious adversities with MPA prohibit its clinical use in MS in its present form.

Myasthenia gravis associated with multiple sclerosis. Epidemiological survey and immunological findings

Patient registers on myasthenia gravis (94 patients) and multiple sclerosis (991 patients) from a population of 1.5 million were reviewed to find patients with both diseases. Seven potential candidates were found, but both diagnoses were confirmed in 2 women only. The first patient had also iritis, the second patient had, besides MG and MS, bronchial asthma and polyarthritis. Both neurological diseases had a relatively mild clinical course. Thymectomy relieved MG symptoms in both patients. Cerebrospinal fluid studies during the follow-up indicated immunoactivation within the central nervous system. Changes in cellular immunity were also noted. The HLA types were different. The combination of these two diseases appears to be more common than expected.

Natural killer (NK) cells in chronic progressive multiple sclerosis patients treated with lymphoblastoid interferon

Natural killer (NK) cell functional activity, as defined by the lysis of 51Cr-labelled K-562 cells, and number, defined phenotypically by anti-Leu-11, are significantly decreased in chronic progressive multiple sclerosis (MS) when compared to normal controls. When age- and sex-matched populations are compared, NK cell functional activity is again significantly reduced in MS compared to controls but not when compared to a control group of other medical disease (OMD). The MS group could be differentiated from the OMD group, however, when results of NK cell functional activity are combined with NK cell phenotype. With the administration of lymphoblastoid interferon daily for 6 months, NK cell activity increased significantly at 48 h and at 1 week. By 1 month, activity decreased to a level slightly above placebo treatment values. The results likely reflect interferon's enhancement of mature NK cell activity combined with a variable effect on recruitment of pre-NK cells.

Lymphocytes subclasses and function in patients with optic neuritis in childhood with special reference to multiple sclerosis

Ten patients with childhood optic neuritis (5 with a single attack of ON and 5 with later MS) were studied at various stages of the disease. Lymphocyte count and function were analysed in the peripheral blood of all patients, 3 repeatedly, and in one they were also analysed in the CSF. T-lymphocytes counts were normal in all but 2 MS cases who had high counts. In acute stages the T4/T8 ratio were high in 1/3 determinations, in recovery low in 2/2 determinations, and in stable stages normal in 6/8 determinations. Lymphocyte function, measured by PHA, ConA and PWM stimulation, was normal in all but one. One patient showed significantly higher T-cell percentages and a high number of stimulated lymphocytes in CSF but a lower count of suppressor cells than in the blood. We found no abnormalities specific to MS nor to childhood MS or to disease activity stage. Rather than peripheral blood, it would seem more worthwhile to study CSF to clarify the pathogenesis of ON and MS.

Myelin basic protein-specific CD4+ cytolytic T-lymphocyte clones isolated from multiple sclerosis patients

In the present report we describe the isolation and characterization of stable, long-term, human T-lymphocyte clones specific for myelin basic protein (MBP) from multiple sclerosis (MS) patients. Isolation of these clones appeared possible only by seeding peripheral blood mononuclear cells into a limiting dilution microculture system containing MBP, autologous irradiated cells and Interleukin-2 (IL-2), thereby minimizing effects of putative suppressor cell populations. All clones obtained were of the CD4+ phenotype. The majority was capable of MBP-specific cytolysis, tested with 51Chromium-labeled autologous Epstein-Barr virus (EBV)-transformed B-cells, coated with MBP, as targets. A few other clones had natural killer (NK) function. All clones produced Interleukin-2 (IL-2) upon adequate stimulation.

Oligoclonal immunoglobulin bands in cerebrospinal fluid of patients with Alzheimer's disease and vascular dementia

We examined serum and cerebrospinal fluid (CSF) of 16 patients with Alzheimer's disease (AD), 28 patients with vascular dementia (VD), their age-matched controls and multiple sclerosis (MS) patients in order to evaluate the humoral immune response within the central nervous system both quantitatively and qualitatively. Intra-blood-brain barrier (BBB) protein synthesis was calculated by CSF IgG index. The presence of oligoclonal banding (OCB) was investigated with agarose isoelectric focusing (IEF) followed by immunoblotting with antihuman IgG. No patient with AD and only 4 patients with VD had slightly elevated IgG indexes, and no statistically significant differences in the indexes were found between the two groups. No bands were found in the CSF of AD patients but 3 VD patients had OCB in both serum and CSF. One VD patient had bands in serum but no bands in CSF. No kappa or lambda free light chains were found in those demented patients with demonstrable bands in the CSF and serum. No OCB were found in control sera and CSF. For comparison, the majority of patients with MS had OCB in CSF. Thus, no consistent increase of intrathecal protein synthesis was found in patients with AD and VD. Methodological differences explain at least part of the conflicting results published earlier.

Oligoclonal and polyclonal synthesis of IgG in the central nervous system: an isoelectric focusing study

The IgG pattern in isoelectric focusing (IEF) has been studied in 90 paired samples of cerebrospinal fluid (CSF) and sera obtained from patients in which intrathecal synthesis of IgG without barrier damage was detectable by Reiber's graph and formula (1980, J. Neurol. 224, 89). Thirty patients were affected by multiple sclerosis (MS), 30 by other inflammatory nervous diseases (OID), and 30 by noninflammatory nervous diseases (NID). At IEF two distinct pathological patterns of CSF IgG were detected: oligoclonal bands (OB), prevailing in the MS group (83% of cases), and a "polyclonal"--i.e., diffuse, uniform--increase of CSF IgG, prevailing in the NID (90%). The OID group was intermediate, 57% of cases with OB and 43% with polyclonal CSF IgG patterns. Overall, only 45 of 90 patients synthesizing IgG in the CNS had CSF OB. This suggests that the CNS immune response can imply either the synthesis of IgG of restricted heterogeneity (i.e., OB) or a polyclonal IgG synthesis, giving in IEF a serum-like pattern to the CSF.

Antibody to myelin constituents: a possible factor in induction of cell-mediated demyelination

Results from this laboratory have demonstrated that 14C-labeled myelin opsonized with antibodies raised to purified CNS myelin in rabbit is phagocytized by cultured macrophages in larger amounts than untreated myelin or myelin opsonized with preimmune serum. The cultured macrophages produced high amounts of radioactive cholesterol ester and triglyceride from the antibody-treated myelin while much less was formed from preimmune serum-treated or untreated myelin. Antiserum to galactocerebroside also greatly enhanced the formation of radioactive cholesterol ester, while that to myelin basic protein as well as to other myelin constituents had little or no effect. Serum from Lewis rats with acute EAE 13-14 days after immunization with whole CNS myelin also stimulated radioactive cholesterol ester formation compared to serum from Freund's adjuvant-injected controls (FAC). Serum from EAE rats as a result of myelin basic protein injection was as active as that from rats with whole myelin injection. No galactocerebroside antibody could be demonstrated in the EAE sera, although a strong immunostaining to myelin basic protein and proteolipid protein was demonstrated. IgG prepared from EAE serum also showed stimulatory effects compared to IgG from FAC serum, but much of the activity was lost, and the possibility that other factors may be involved is discussed. These experiments provide evidence that myelin phagocytosis and digestion by macrophages is enhanced by the presence of antibody to myelin. In EAE this antibody may leak into CNS with the breakdown of the blood-brain barrier.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoglobulin and C3 abnormalities in acute psychiatric disorders

In a prospective study of 54 patients with acute psychiatric disorders, elevated absolute concentrations of immunoglobulin G (IgG), IgM and complement factor C3 were found in the cerebrospinal fluid (CSF) in seven (P less than 0.001), eight (P less than 0.01) and in four patients, respectively, and in serum in seven, 19 and 17 patients (P less than 0.001 in all), respectively, quantified by automated immunoprecipitin nephelometry in unconcentrated CSF and serum and compared with neurological controls with peripheral neurological symptoms. Elevation of the IgG-index was observed in seven patients (P less than 0.001) and CSF/S albumin ratio in four patients (P less than 0.05). The presence of oligoclonal IgG bands was found in 22 patients (P less than 0.001). The results suggest that viral infections, inflammatory and autoimmune processes may have significance in the etiopathogenesis of acute psychiatric disorders.

Cell-mediated immunological status in multiple sclerosis patients

In vitro lymphocyte proliferation in response to allogeneic pooled cells, mitogens (PHA, Con A and PWM), and PPD was measured in 67 patients with clinically definite MS and in 67 age and sex-matched controls. Overall, dose-response curves in the two groups were similar, but response to PHA and PWM was significantly greater among patients, and a greater percentage of patients failed to respond to peak and suboptimal PPD concentrations. There was a reduced response to allogeneic pooled cells in Dw2 positive controls, and, in both patients and controls, a tendency towards a higher PPD response in Dw2 positive males. The results suggest that there is some alteration of balance of immune regulation in MS, which is slightly affected by Dw2 status.

Myelin basic protein and demyelinating diseases

Myelin basic protein (MBP) is a major protein component of myelin sheath. Primarily because of its ability to induce experimental allergic encephalomyelitis (EAE) in animals, this protein has been considered to play an important role in the pathogenesis of multiple sclerosis (MS), which is one of the most common demyelinating diseases. Its precise measurement in the cerebrospinal fluid (CSF) has been uncommonly difficult, mainly due to immunoheterogeneity of MBP or MBP-like material. More recently, highly sensitive radioimmunoassay techniques utilizing well-characterized antisera have been developed that facilitated its use in the management of MS. The clinical course of MS is highly variable, and the disease is characterized by periods of remission and relapses. Many studies have demonstrated the release of MBP during relapses and elevated levels of MBP in the CSF can be detected if lumbar puncture is performed within 7 days of the onset of neurologic symptoms suggestive of MS. However, the presence of MBP is not an absolute indicator of MS, as elevated MBP levels are also frequently observed in other demyelinating diseases.

Serial immunological studies in multiple sclerosis patients treated systemically with human alpha interferon

A battery of immunological functions was studied over a 2-year period in conjunction with a placebo-controlled trial of natural human alpha interferon in patients with multiple sclerosis. IgG synthesis was increased both systemically and intrathecally by administration of interferon; however, there were only minor changes in cerebrospinal fluid oligoclonal bands. Levels of helper and suppressor T lymphocytes fluctuated independently of clinical exacerbations, although mean helper/suppressor ratios were higher in multiple sclerosis patients than in controls and increased further during interferon treatment. Cerebrospinal fluid myelin basic protein and antibodies to basic protein were not affected by exacerbations or by interferon administration. Circulating IgG antibodies induced by interferon treatment appeared to be directed at a non-interferon contaminant of the preparation. None of the assays was a consistent indicator of disease activity or of clinical response to interferon.

Impaired measles virus-specific cytotoxic T cell responses in multiple sclerosis

To assess whether an virus-specific immune defect may be associated with multiple sclerosis (MS), we have examined the ability to generate measles virus-and influenza virus-specific cytotoxic T cells (CTL) in patients with MS, normal individuals, and other disease controls (ODC). The mean (+/- SEM) measles virus-specific CTL response for normal individuals and ODC was 26.9 +/- 2.9% (N = 17) and 26.7 +/- 2.8% (N = 13) specific lysis, respectively. In contrast, the capacity of MS patients to generate measles virus-specific CTL was markedly diminished. Peripheral blood lymphocytes from MS patients stimulated with measles virus lysed their measles virus-infected autologous B cell line at a group mean level of 6.0 +/- 1.4% (N = 16) specific lysis. MS patients had significantly lower measles virus-specific CTL responses than normal individuals (p less than 0.00001) or ODC (p less than 0.0001). Importantly, this lowered response did not reflect a generalized depressed cytolytic activity of MS patients, since influenza virus-specific CTL and NK activity from these patients were comparable to normals and ODC. Thus, in MS there is a significant depression of measles virus-specific CTL which suggests that this virus-specific immune dysfunction may play a role in the pathogenesis of this disorder.

Abnormalities of serum and plasma components in patients with multiple sclerosis

Qualitative and quantitative abnormalities in protein and non-protein components of serum and plasma in patients with multiple sclerosis have been the subjects of numerous reports. In this review many of the more recent observations are documented and evaluated. It is concluded that at present the welter of information that has been gathered does not contribute in any major, coherent way to our understanding of the etiology or pathogenesis of the disorder. Several of the abnormalities that have been observed may be future candidates for biochemical markers for multiple sclerosis; at present none is sufficiently reliable, distinctive or easily performed to warrant the status of a useful diagnostic or prognostic test.

Optic neuritis during lactation

The condition called "lactation optic neuritis" has been previously considered a clinical entity of its own. Four women, who developed optic neuritis within 1-12 months while breast-feeding their infants, were investigated ophthalmologically and neurologically in order, to find specific clinical features for this condition. The course of the disorder was similar to classic optic neuritis without lactation. The clinical history and laboratory findings in three of the four patients suggested a demyelinating disorder. It is possible that the decreased immunosuppressive activity just after pregnancy induces the manifestation of an underlying demyelinating disease. The existence of "lactation optic neuritis," however, is questioned as a separate entity of its own. Lactation together with decreased immunosuppression may merely act as a provocateur in the onset of optic neuritis, which in many cases is the first clinical manifestation of incipient multiple sclerosis.

Prostaglandin levels in cerebrospinal fluid from multiple sclerosis patients in remission and relapse

Radioimmunoassay (RIA) techniques have been employed to determine prostaglandin (PG) levels in the cerebrospinal fluid (CSF) from multiple sclerosis (MS) patients in remission and relapse and in subjects with other neurological diseases (OND). PGE and PGF2 alpha concentrations in spinal fluid from MS patients in relapse were significantly lower than values estimated during remission and in individuals with OND of the central nervous system (CNS). These observations are discussed in relation to the clinical state of patients with demyelinating disease together with a consideration of the concept that disordered immune mechanisms contribute a central role in the pathogenesis of MS.

Cytotoxic activity of peripheral blood and cerebrospinal fluid lymphocytes from patients with multiple sclerosis and other neurological diseases: analysis at the single cell level of the relationship of cytotoxic effectors and interferon-producing cells

The production of interferon (IFN alpha) in relationship to NK and ADCC activity of peripheral blood and cerebrospinal lymphocytes was examined at the single cell level in patients with multiple sclerosis (MS) and other neurological diseases (OND) compared with age- and sex-matched controls. IFN-producing cells were assessed by indirect immunofluorescent scoring of cytoplasmic IFN+ cells. Peak production of cytoplasmic IFN alpha in nylon wool-passed ( NWP ) cells occurred between 5 and 17 hr in vitro under the inductive stimulus of MOLT 4, K562, or antibody-coated Chang liver cells. The proportion of K562- and MOLT 4-induced IFN alpha-positive cells in the total lymphocyte and target-binding cell (TBC) population was significantly lower in MS NWP -peripheral blood lymphocytes (PBL) than in OND and normal controls; this was in direct relationship to a decreased percentage of NK cells in MS PBL. In contrast MS cells responded the same as controls (total IFN+ cells) or higher than controls (IFN+-TBC) after IFN alpha induction by antibody-coated Chang, the ADCC target, in parallel with elevated ADCC activity by MS PBL. MS CSF contained a higher proportion of total IFN+ cells but a similar proportion of IFN+-TBC as their homologous NWP PBL population. In OND CSF, both the percentage of total IFN+ and the percentage of IFN+-TBC were higher than in OND blood and higher than their respective MS CSF populations. The relationship of IFN-producing cells in the central nervous system (CNS) to putative cytotoxic cells is discussed.

Immunological treatment of multiple sclerosis

Immunosuppressive treatment of multiple sclerosis (MS) is based on the autoimmune hypothesis for which the main evidence is the close histological similarity between the human disease and chronic relapsing EAE. Although controlled trials indicate that ACTH is effective in accelerating recovery from relapses, long term ACTH or oral steroids are ineffective. Two controlled trials have suggested a beneficial effect of azathioprine, but neither was conducted "blind" and neither was sufficiently convincing to cause the widespread adoption of azathioprine by neurologists. One controlled trial, also not blind, reported a beneficial effect of an intensive course of cyclophosphamide, but this hazardous treatment will not be widely adopted unless other trials confirm this result. The converse hypothesis that MS is due to a deficient immune response to a virus has led to trials of immunostimulation. Interferon and levamisole have proven ineffective so far, but transfer factor slowed disease progression in one well conducted trial.

Cerebrospinal fluid IgG bands and virus-specific IgG, IgM, and IgA antibodies in herpes simplex virus encephalitis

To characterize the immune response of the central nervous system in herpes simplex virus (HSV) encephalitis, cerebrospinal fluid (CSF) specimens of 7 biopsy proven and 7 presumptive herpes simplex virus (HSV) encephalitis patients were studied, using sodium dodecyl sulfate polyacrylamide gel electrophoresis for the presence of CSF IgG bands, and solid-phase enzyme immunoassays for HSV-specific antibodies. IgG bands were detected in all CSF specimens of the patients, as early as day 6 and up to day 1088. A novel, unidentified, 120 000 dalton polypeptide was found in the CSF of most of the patients, in a total of 25/50 specimens, but not in the controls. This polypeptide was evident by day 6, its intensity fluctuated and it was present in specimens collected as late as day 855. HSV-specific antibodies, of either IgG, IgM, or IgA class, were not detected in the CSF during the first week of illness. IgG antibodies appeared later in all patients and persisted to the end of the follow-up of 3 years. The fact that CSF IgG bands were present in some patients before the appearance of HSV antibodies, and also persisted longer, suggests that the IgG response is not restricted to HSV-specific antigenic determinants.