Soluble and cell surface ICAM-3 in blood and cerebrospinal fluid of patients with multiple sclerosis: influence of methylprednisolone treatment and relevance as markers for disease activity

OBJECTIVE: The expression of intercellular adhesion molecule-3 (ICAM-3), a member of the Ig supergene family, is restricted to immune competent cells. Expression of soluble and cell surface ICAM-3 (s- and c-ICAM-3) is preferentially seen in the state of low activation of the immune system. We studied the relevance of the expression levels of s- and c-ICAM-3 in cerebrospinal fluid (CSF) and blood as markers for disease activity as well as the influence of high-dose methylprednisolone (MP) treatment upon the expression of s- and c-ICAM-3 in blood of patients with multiple sclerosis (MS). MATERIALS AND METHODS: A total of 33 patients (relapses n = 25, remission n = 8) with relapsing-remitting MS were included into the study. CSF and blood were acquired from all of them. Of the patients 24 were treated with high-dose MP. In those, blood was additionally collected at the 10th day of the therapy and after 3 months. Expression of c-ICAM-3 was determined by two colour FACS analysis, whereas the concentration levels of s-ICAM-3 were measured by ELISA. RESULTS: In CSF we detected a significant decrease of the expression levels of c-ICAM-3 on CD3+ T cells in 25 patients suffering from an acute relapse in contrast to 8 patients with remission (P= 0.04). In comparison to the levels before treatment and after 3 months, at the 10th day of MP treatment we obtained highly significant changes of the expression values of c-ICAM-3 both on CD3+ T cells (P = 0.0004; P= 0.005) and CD14+ monocytes/macrophages (P =0.0006; P=0.008) on the 10th day of high-dose MP treatment from 24 MS patients. CONCLUSION: The increase of ICAM-3 levels might indicate the anti-inflammatory effect of the MP treatment. It could be interesting to search for similar effects investigating the new immune modulatoring therapy forms of MS.     

Analysis of lymphocyte subpopulations in cerebrospinal fluid and peripheral blood in patients with multiple sclerosis and inflammatory diseases of the nervous system

We analysed different subsets of lymphocytes from peripheral blood (PB) and cerebrospinal fluid (CSF) by flow cytometry in order to determinate alterations in patients with multiple sclerosis (MS) in acute relapse and viral inflammatory neurological disease (IND). We found increased levels of adhesion molecules (LFA-1 and β₁ integrin) in the CSF of patients with MS and IND compared to NIND. CD4 ⁺/CD8 ⁺ ratio was significantly higher in CSF of MS as compared with all groups analysed and compared with PB. We detected a significantly higher expression of the interleukin-2 receptor in PB of MS patients when compared with other groups. In patients with IND a significant higher expression of the interleukin-2 receptor was found in the CSF compared with MS and NIND. Our findings indicate that the activation of T lymphocytes primarily occurs in the peripheral immune compartment in MS and the increase of adhesion molecules in CSF is related to inflammatory disorders and not only to MS.     

CD4 and CD8 lymphocyte subsets in cerebrospinal fluid and peripheral blood from patients with multiple sclerosis, meningitis and normal controls

Objectives - To study the distribution of CD4⁺ and CD8⁺ T-cell subsets in cerebrospinal fluid (CSF) and peripheral blood from patients with multiple sclerosis (MS), meningitis, other neurological diseases and healthy controls.
Material and methods - The expression of markers for naive and memory cells (CD45RA⁺ and CD45RO⁺), and helper/inducer cells (CD29⁺) on CD4⁺ cells as well as CD45RO⁺ and killer/effector (S6F1⁺) on CD8⁺ cells was investigated in cerebrospinal fluid (CSF) and peripheral blood from patients with multiple sclerosis (n=28), meningitis (n = 13), other neurological diseases (n = 16), and healthy controls (n = 16) by 2-color flow cytometry.
Results - The majority of T cells in the CSF of the 4 groups exhibited the phenotype of memory cells (CD45RO⁺) on both CD4⁺ and CD8⁺ cells. The proportion of helper/inducer (CD29TD4⁺ in CD4⁺) cells was also larger in the CSF compared to peripheral blood in the 3 patient groups and controls investigated. In contrast, CD8⁺ cells with killer/effector (S6F1+) phenotype were fewer in CSF compared to peripheral blood in all 4 groups. There were no significant differences between patients and controls regarding the distribution of these activation markers in the CSF or peripheral blood.
Conclusion - Our observations support the notion that activated T cells of both CD4⁺ and CD8⁺ phenotype selectively pass the blood-brain barrier under both pathological and normal conditions.     

CD45RA+ ICAM-3+ lymphocytes in cerebrospinal fluid and blood as markers of disease activity in patients with multiple sclerosis

OBJECTIVES: Autoreactive T cells targeted against antigens of the myelin sheath are suggested to play an important role in the pathogenesis of multiple sclerosis (MS). Naive (CD45RA+) T cells and intercellular adhesion molecule-3 (ICAM-3) are markers for un-activated lymphocytes. This study was performed to investigate, whether the expression levels of these antigens both on cerebrospinal fluid (CSF) and peripheral blood lymphocytes can be used as activity markers in MS. MATERIALS AND METHODS: Corresponding blood and CSF samples were obtained from 31 patients with relapsing-remitting MS. Of the 31 MS patients 23 were suffering from acute relapses at the time of examination and all of them were treated with high-dose methylprednisolone (MP). Blood was collected again on the 10th day of therapy and after 3 months. The control group consisted of 12 healthy persons. Two-color flow cytometry was performed to evaluate the percentage of both CD45RA+ and ICAM-3+ cells within the lymphocyte population. RESULTS: The percentage of CD45RA+ ICAM-3+ cells in the CSF of MS patients with relapses was significantly increased compared to patients in remission (P<0.05). In blood, a significantly lower percentage of CD45RA+ ICAM-3+ lymphocytes was found in both patient groups compared to healthy controls (Relapse: P<0.05, Remission: P<0.10). Additionally, we found a significant increase (P < 0.01) in the percentage of CD45RA+ ICAM-3+ lymphocytes in blood of MS patients suffering from acute relapse on the 10th day of high-dose MP treatment. CONCLUSION: Our data suggest that the percentage of CD45RA+ ICAM-3+ lymphocytes in CSF can be used as marker of disease activity in MS patients.     

Adhesion molecules in multiple sclerosis: relation to subtypes of disease and methylprednisolone therapy

OBJECTIVES: To determine levels of adhesion molecules in blood and cerebrospinal fluid (CSF) samples from patients with different subtypes and activities of multiple sclerosis (MS) and to assess the effect of intravenous methylprednisolone sodium succinate treatment on the levels of soluble adhesion molecules. DESIGN: The expressions of very late activation antigen 4 (VLA-4), lymphocyte function associated antigen 1 (LFA-1), vascular cell adhesion molecule 1 (VCAM-1), and intercellular adhesion molecule 1 (ICAM-1) were determined immunocytochemically, and levels of soluble VCAM-1, ICAM-1, and E-selectin, by means of enzyme immunoassay technique. The volumes of T2- and T1-weighted MS plaques and brain atrophy were determined by means of the semiautomatic magnetic resonance imaging (MRI) segmentation technique. SETTING: A university hospital in Finland. PATIENTS: One hundred subjects (71 patients with MS and 29 healthy control subjects). The subtypes of MS were relapsing-remitting (RRMS [n = 26]), secondary progressive (SPMS [n = 20]), and primary progressive (PPMS [n = 25]). RESULTS: In patients with RRMS and SPMS, the expressions of VLA-4 and LFA-1 on immune cells from blood were at least 1.5- to 3-fold higher than in controls (RRMS, P = .002 and P<.001, respectively; SPMS, P = .03 and P =.001, respectively). In RRMS, LFA-1 and ICAM-1 expression in blood was more up-regulated than in SPMS (P = .03 and P = .01, respectively). The expressions of adhesion molecules on CSF lymphocytes in RRMS and SPMS were of similar magnitude, but the proportions of CSF VLA-4- and LFA-1-expressing lymphocytes were 3- to 4-fold higher than in controls (P = .04 and P = .008, respectively). The levels of serum soluble VCAM-1 were higher in SPMS than in RRMS (P = .005) or PPMS (P = .04). Intravenous methylprednisolone treatment of patients with RRMS in exacerbation caused a significant reduction in the serum levels of soluble VCAM-1 and E-selectin (P<.001). In SPMS, the volumes of T2-weighted plaques correlated with the serum level of soluble ICAM-1 (r = 0.64; P = .03). CONCLUSIONS: Up-regulated adhesion molecules in blood and CSF indicate sustained potential for inflammation in the CNS throughout the clinical spectrum of MS. Therapies interfering with cell adhesion may be of key importance in suppressing MS.     

Blood-CSF barrier integrity in multiple sclerosis

Introduction - In about 20% of MS patients an increased CSF/serum albumin quotient (Q_Alb) has been observed. The reason for this blood-CSF barrier dysfunction is yet unclear.
Subjects and methods - Q_Alb values from 48 MS patients in relapse were correlated with parameters of active CNS lesions as measured by gadolinium-DTPA MRIs. Q_Alb values from 20 MS patients without relapse served as controls. Results - Mean Q_Alb values (×10³) of a group with spinal cord lesions (7.6±3.6; n=16) differed significantly from those of a control group (4.6±1.5; n=20; p<0.005) as well as from those of a group with supratentorial lesions (5.0±1.8; n=18; p<0.05), and were higher than those of a group with infratentorial lesions (5.8±2.8; n=14). Q_Alb values of patients with a spinal lesion tended to decrease with increasing time intervals between onset of relapse and lumbar puncture. Conclusions - The data is in consent with the present knowledge on flow dynamics of both extracellular fluid and CSF. As a clinical consequence, increased Q_Alb values in MS patients may hint at an active spinal or, less likely, infratentorial lesion.     

Parkinson's disease and immunological abnormalities: increase of HLA-DR expression on monocytes in cerebrospinal fluid and of CD45RO+ T cells in peripheral blood

The etiology of Parkinson's disease is mainly unknown. Immune abnormalities have been described, but the cause of such abnormalities has not been resolved. We examined by two-colour flow cytometry HLA-DR antigen expression on monocytes from cerebrospinal fluid (CSF) and blood and, moreover, lymphocyte subpopulations (CD4⁺ CD45RO⁺, CD4⁺ CD45RA⁺, CD8⁺ CD11b^+high) in peripheral blood from patients with Parkinson's disease compared with age-matched patients with other neurological diseases (OND) and tension headache. We found higher HLA-DR expression on CSF monocytes compared with blood monocytes. This difference was restricted to Parkinson's disease patients. T helper cell analysis revealed a decreased percentage of CD45RA⁺"naive" and an increased percentage of CD45RO⁺"memory" T cell subset from CD4⁺ T cells in peripheral blood of patients with Parkinson's disease compared with patients with tension headache. The proportions of CD8⁺ CD11b^+high"suppressor" T cells remained unchanged, among the three patient groups compared. A selective loss of CD4⁺ CD45RA⁺ cells, previously observed in diseases like multiple sclerosis and Down's syndrome as compared with healthy controls suggests a common immunological abnormality in neurological disorders.     

Chemokine receptor expression on T cells in blood and cerebrospinal fluid at relapse and remission of multiple sclerosis: imbalance of Th1/Th2-associated chemokine signaling

The expression of chemokine receptors on lymphocytes in the blood and CSF of multiple sclerosis (MS) patients was analyzed at relapse and remission. Both CD4+ and CD8+ cells in CSF at relapse were enriched for Th1-type receptors CXCR3 and CCR5 expression, and were reduced for Th2-type receptors CCR3 and CCR4 expression compared with those of the blood. CCR1 and CCR2 expressions on T cells were increased in CSF and blood, respectively. At remission, CCR5 expression, but not CXCR3 expression, was reduced in CSF CD4+ cells. A biased Th1/Th2 balance may play a critical role in active inflammation and CCR5 on CSF CD4+ cells is a good marker of the disease activity.     

FTY720 attenuates lesional interleukin-17+ cell accumulation in rat experimental autoimmune neuritis

Aims : Experimental autoimmune neuritis (EAN) is a well-known animal model of human demyelinating polyneuropathies. Here we have studied the spatiotemporal accumulation of interleukin (IL)-17⁺ cells in sciatic nerves of EAN rats and effects of FTY720, an agonist of sphingosine-1-phosphate (S1P) receptors. Methods : In this study, we examined the spatiotemporal expression of IL-17 using immunohistochemistry and RT-PCR, and analysed the IL-17⁺ cell proportion in blood and lymph nodes using flow cytometry. Results : In sciatic nerves of EAN rats, IL-17⁺ cells were mainly found to concentrate around blood vessels and IL-17⁺ cell accumulation was temporally correlated with severity of neurological signs. FTY720, which has been shown to reduce severity of EAN, attenuated accumulation of IL-17⁺ cells in sciatic nerves, decreased IL-17⁺ cell proportion in peripheral blood, but increased IL-17⁺ cell proportion in lymph nodes, suggesting the involvement of S1P signal pathway in regulating IL-17⁺ cell trafficking. Conclusions : our data are consistent with the possibility that IL-17⁺ cells might contribute to the pathogenesis of EAN and the S1P signal pathway may be involved in the in vivo trafficking of IL-17⁺ cells.     

Nitric oxide as an activity marker in multiple sclerosis

Nitric oxide (NO) molecules have one of the most important roles in the pathogenesis of multiple sclerosis (MS). It has been stated that a continuous and high concentration of NO metabolites in CSF and in the serum of MS patients in relapse may cause toxic damage to myelin and oligodendroglia. The aim of this study was to investigate whether NO is a marker of disease activity and is correlated with other disease activity markers such as active lesions on brain magnetic resonance imaging (MRI) and increased immunoglobulin G (IgG) index. Cerebrospinal fluid (CSF) and peripheral serum (PS) samples were taken from patients with definite MS (n = 24) during relapse and remission and from control subjects (n = 18). The Griess reaction was used to measure the NO metabolites, nitrite and nitrate in CSF and PS. Cranial MRI was carried out with triple dose (0,3 mmol/kg) gadolinium and the IgG index was determined. Nitrite and nitrate concentrations (NNCs) of CSF were 11.16 +/- 8.60 micromol/ml in relapse and 6.72 +/- 3.50 micromol/ml in remission, whereas in PS they were 12.89 +/- 7.62 micromol/ml during relapse and 12.35 +/- 6.62 micromol/ml during remission. In control subjects NNCs in CSF and PS were 7.42 +/- 2.81 micromol/ml and 4.37 +/- 1.63 micromol/ml respectively. NNCs in CSF during relapse period were significantly higher than those of both remission phase and control subjects (p = 0.000). Although serum NNCs did not differ in relapse and remission, they were still higher than normal controls. Validity analysis revealed that NNC measurement in CSF was 71 % specific and 66 % sensitive to disease activity. The most important result was the significant correlation of increased NNCs with the existence of active lesion in cranial MRI and an increase in IgG index (p < 0.05).In conclusion, these results add background data to assist in further outlining the possible role of NO in the pathogenesis of MS. Together with the other markers it may be used as an activity marker in relapses of MS.     

T cell subsets in multiple sclerosis: a serial study

The relevance of abnormalities in the distribution of peripheral blood T lymphocyte subsets to the clinical manifestations of multiple sclerosis is not firmly established. A clinical and immunological follow-up of relapsing-remitting multiple sclerosis patients was performed in order to study the relationship of immune changes with the clinical course of the disease. Twenty patients were monitored monthly during a mean time of nine months for peripheral blood lymphocyte subsets (CD3, CD4, CD8, CD19), including the immunoregulatory subsets CD4CD29 (helper-inducer), and CD4CD45RA (suppressor-inducer) and activated T helper cells (CD4CD25) by flow cytometry. A total of 14 untreated relapses was included. The most significant observations were a decrease in T suppressor-inducer CD4⁺ CD45RA⁺ subset during clinical relapses ( P = 0.028) that was also detectable one month before ( P = 0.020) and the lack of changes in CD4⁺ CD29⁺ and CD8⁺ T cells. In addition, variations in the percentage of CD4⁺CD25⁺ activated T helper cells were not associated with clinical exacerbations. These results indicate the existence of a temporal association of immune changes in peripheral blood, but not activation, with the clinical manifestations of multiple sclerosis.     

Determination of soluble ICAM-1 and TNFalphaR in the cerebrospinal fluid and serum levels in a population of Brazilian patients with relapsing-remitting multiple sclerosis

Cytokines and adhesion molecules have been implicated in the pathogenesis of multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system. In this study we analyzed intrathecal (CSF) and serum levels of soluble intercellular adhesion molecule (ICAM-1) and TNFalphaR (60kD) from 20 patients with clinically definite MS during acute relapse or stable disease. Comparing to control groups of healthy individuals and patients with intervertebral herniated disc, MS patients showed increased levels (p< 0.001) of sICAM-1 and TNFalphaR in both serum and CSF samples. Regardless stage of disease there was no significant difference in the levels of sICAM-1 during acute relapse (657+/-124.9 ng/ml) or remission (627+/-36.2 ng/ml). A steady increase of TNFalphaR (60kD) in both serum and CSF, indicate the existence of a continuous inflammatory process within the brain tissue of MS patients despite absence of clinical signs of disease activity.     

Detection of the 14-3-3 protein in the cerebrospinal fluid of Japanese multiple sclerosis patients presenting with severe myelitis

Recent studies showed that the 14-3-3 protein is detectable in the cerebrospinal fluid (CSF) of prion-unrelated neurological diseases, such as meningoencephalitis and myelitis. To investigate the possible association between the amounts of the 14-3-3 protein in the CSF and the clinical severity of multiple sclerosis (MS), its levels were determined by Western blot in the CSF of the patients with relapsing-remitting MS (RRMS) (n=10), secondary progressive MS (SPMS) (n=7), primary progressive MS (PPMS) (n=2), and non-MS inflammatory diseases of the CNS (n=5). The 14-3-3 protein was identified in seven CSF samples, including four patients with SPMS in acute relapse, one with SPMS in remission accompanied by fresh cerebral infarction, one with RRMS in acute relapse, and one with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy. The patients positive for the CSF 14-3-3 protein immunoreactivity showed more severe disability and higher levels of pleocytosis, protein, IgG, beta2-microglobulin, and neuron-specific enolase in the CSF, compared with those negative for its immunoreactivity. Four of these patients exhibited extensive lesions distributed along multiple vertebral segments in the spinal cord on MRI. In contrast, none of the MS patients without an extensive involvement of the spinal cord showed the CSF 14-3-3 protein immunoreactivity. These results suggest that detection of the 14-3-3 protein in the CSF provides a marker for severe inflammation-induced extensive damage of the central nervous system tissues responsible for poor therapeutic responses and irreversible neurological deficits in MS.     

CD45RA+ ICAM-3+ lymphocytes in interferon-beta1b-treated and -untreated patients with relapsing-remitting multiple sclerosis

OBJECTIVES: Multiple sclerosis (MS) is believed to be an autoimmune disease of the human central nervous system mediated by autoreactive T cells. Interferon-beta1b (IFN-beta1b) has been shown to be effective in reducing disease activity defined by clinical and magnetic resonance imaging (MRI) criteria in relapsing-remitting MS (RRMS). Yet, the exact mechanisms by which these benefits are achieved remain unknown. CD45RA is a marker for naive T lymphocytes and intercellular adhesion molecule-3 (ICAM-3) is expressed on resting lymphocytes. MATERIAL AND METHODS: Forty-eight patients with RRMS, 24 of them treated with recombinant IFN-beta1b and 24 untreated, were enrolled in this prospective study over 18 months. We investigated the percentage of CD45RA+ ICAM-3+ cells within the total lymphocyte subset in the peripheral blood serially every 3 months and in CSF once at baseline. Detailed clinical examination including Expanded Disability Status Scale (EDSS) score was performed every 3 months and cranial MRI scans were assessed every 6 months. RESULTS: We found a temporary increase in the CD45RA+ ICAM-3+ lymphocyte ratio in peripheral blood of both untreated and IFN-beta1b-treated RRMS patients. Moreover, we determined a significant negative correlation (r = -0.5874; P < 0.01) between age as well as the EDSS score (r = -0.3629; P < 0.05) and the percentages of CD45RA+ ICAM-3+ lymphocytes in peripheral blood but a positive correlation between EDSS score and the CD45RA+ ICAM-3+ ratio (r = 0.3913; P < 0.05) in the CSF at baseline. CONCLUSION: CD45RA+ ICAM-3+ lymphocyte ratio in peripheral blood might indicate immunosenescence in MS. However, from our data it cannot be finally concluded whether it is also influenced by IFN-beta1b treatment.     

Myelin basic protein antibodies in the serum and CSF of multiple sclerosis and subacute sclerosing panencephalitis patients

A solid-phase radioimmunoassay was developed for the detection of myelin basic protein antibodies of immunoglobulin G (IgG) class. Purified basic protein of myelin (MBP) was adsorbed onto polystyrene beads, followed by incubation in dilutions of serum or cerebrospinal fluid (CSF). ¹²⁵I-labelled anti-human IgG was used to quantify antibodies bound to the solid-phase. The assay was optimized in tests with rabbit antibodies to MBP and with ¹²⁵I-labelled anti-rabbit IgG.
Serum and CSF specimens from 41 multiple sclerosis (MS), 16 subacute sclerosing panencephalitis (SSPE) and 58 control patients were tested for MBP antibodies. No statistically significant differences were found between MS and control patient groups, but the subgroup of acute MS patients had slightly elevated ( P 0.02) antibody levels in their CSF specimens. The SSPE patients had markedly elevated levels ( P 0.001) of antibodies to MBP in their CSF specimens.     

V region T cell receptor repertoire in Parkinson's disease

Introduction - Restricted usage of Vα and β genes has been found in several diseases, which exert autoreactive T cells. So far no information on T cell receptor (TCR) usage in degenerative diseases is available. Since T cells may be involved in pathogenesis of Parkinson's disease, the analysis of the TCR repertoire is of importance. Material and methods - We have tested the frequency of 6 Vβ-subtypes and the most common Vα-subfamily on peripheral blood lymphocytes in 21 PD patients and 20 controls, separately on CD4⁺ and CD8⁺ T cells. For our study Diversi - T™, the first available Mab set specific for TCR V regions, was used. Results -As a results, no significant differences were found with one exception, i.e., lower frequency of Vβ8(a) expression on CD8⁺ T cells in PD patients than in controls. Conclusion - The failure of preferential usage or lack of usage of the tested V-chain alleles by CD4⁺ T cells argues against an involvement of helper T cells in PD induction.     

Relapses in multiple sclerosis are associated with increased CD8+ T-cell mediated cytotoxicity in CSF

MS is thought to be mediated by CD4(+) T-helper cells. To investigate the importance of CD8(+) cytotoxic T-cells in MS we analyzed peripheral blood T-cells by DNA microarray, and plasma and CSF levels of granzymes from MS patients and controls. Cytotoxic gene expression was decreased in peripheral T-cells from RRMS patients whereas plasma levels of granzymes were unchanged. However, granzyme levels were elevated in the CSF of RRMS patients at relapse compared with controls and remission. Thus, CD8+ T-cell-mediated cytotoxicity is confined to the CSF/CNS compartment in RRMS patients and may be involved in the immunopathogenesis of clinical relapses.     

Varicella-zoster virus at relapses of multiple sclerosis

Abstract The possible participation of different herpes viruses was studied during exacerbations of multiple sclerosis (MS). We searched for the presence of DNA from the following herpes viruses: varicella zoster virus (VZV), herpes-simplex viruses 1 and 2; Epstein-Barr virus (EBV) and human herpes-virus-6 (HHV6) in mononuclear cells from patients with MS during relapse (n = 40), MS during remission (n = 131) and controls (n = 125). Additionally, immune cells containing viral antigens were quantified by flow cytometry, and VZV load was determined by real time PCR in 2 MS patients at various times during relapse and remission. DNA from VZV was found in 95% of MS patients during relapse and in 17% during remission; all controls were negative; by contrast, DNA from HHV6 was found in 24% of MS patients during relapse and in 2% during remission; DNA from herpes simplex viruses was not found in any subject; and DNA from EBV was found in a similar percentage of subjects from all groups. Sequential quantification of VZV-load showed a curve that increased during relapse and disappeared at remission. Also, VZV antigens were found inside a large number of immune cells from MS patients during relapse as compared with MS patients on remission and controls. In the typical forms of VZV infection, varicella and herpes-zoster, DNA from VZV is found in mononuclear cells exclusively during brief periods at the beginning of the active infection, but not during latency; thus, the conspicuous presence of VZV during relapses of MS may indicate a period of active infection and suggests the participation of VZV in the pathogenesis of MS.     

Intrathecal synthesis of anti-myelin basic protein IgG in HIV-1+ patients

Human immunodeficiency virus type 1 (HIV-1)-infected individuals frequently develop a broad spectrum of neurological syndromes, classified as HIV-1-associated cognitive/motor complex. Diffuse demyelination of hemispheric white matter is a commonly observed in HIV-1 infected brain, but the events leading to myelin destruction are still obscure. Since oligodendrocyte infection by HIV-1 is not proven as yet, myelin damage in HIV-1 infection may result from indirect mechanisms such as the excessive release of myelinotoxic substances or the triggering of autoimmune responses directed to myelin constituents. To verify the latter hypothesis, we searched for elevated anti-myelin basic protein (MBP) IgG levels in the cerebrospinal fluid (CSF) and serum of 25 patients with HIV-1 infection, 12 with multiple sclerosis (MS), and 9 with non-inflammatory neurological diseases (NIND). CSF, but not serum, anti-MBP IgG levels were more frequently elevated in HIV-1⁺ (16/25, 64%) than in MS (3/12, 25%) or NIND (0/9) patients. By using the anti-MBP IgG index, the anti-MBP IgG antibody specificity index (ASI), and the search for anti-MBP oligoclonal IgG, we ascertained that anti-MBP IgG were produced within the CNS in 13 of 25 (52%) HIV-1⁺, in 6 of 12 (50%) MS, and in none of NIND patients. The incidence of increased CSF anti-MBP IgG levels was higher among HIV-1⁺ patients at stage II–III (4/4, 100%) or at stage IV B (7/9, 78%) than among those at stage IV C–IV D (5/12, 42%). Although our data indicate that intrathecal anti-MBP IgG may occur early during HIV-1 infection and that they are more common in patients with HIV-1-associated cognitive/motor complex, the possible demyelinating role of these antibodies remains to be demonstrated.