B cell activation in multiple sclerosis

Cerebrospinal Fluid IgM Levels in Association With Inflammatory Pathways in Multiple Sclerosis Patients

Background

Intrathecal immunoglobulin M (IgM) synthesis has been demonstrated in the early disease stages of multiple sclerosis (MS) as a predictor factor of a worsening disease course. Similarly, increased cerebrospinal fluid (CSF) molecules related to B-cell intrathecal activity have been associated with a more severe MS progression. However, whether CSF levels of IgM are linked to specific inflammatory and clinical profile in MS patients at the time of diagnosis remains to be elucidated.

Methods

Using customized Bio-Plex assay, the protein levels of IgG, IgA, IgM, and of 34 other inflammatory molecules, related to B-cell, T-cell, and monocyte/macrophage activity, were analyzed in the CSF of 103 newly diagnosed relapsing–remitting MS patients and 36 patients with other neurological disorders. CSF IgM levels were also correlated with clinical and neuroradiological measures [advanced 3-T magnetic resonance imaging (MRI) parameters], at diagnosis and after 2 years of follow-up.

Results

A 45.6% increase in CSF IgM levels was found in MS patients compared to controls (p = 0.013). CSF IgM levels correlated with higher CSF levels of CXCL13 (p = 0.039), CCL21 (p = 0.023), interleukin 10 (IL-10) (p = 0.025), IL-12p70 (p = 0.020), CX3CL1 (p = 0.036), and CHI3L1 (p = 0.048) and were associated with earlier age of patients at diagnosis (p = 0.008), white matter lesion (WML) number (p = 0.039) and disease activity (p = 0.033) after 2 years of follow-up.

Conclusion

IgMs are the immunoglobulins mostly expressed in the CSF of naive MS patients compared to other neurological conditions at the time of diagnosis. The association between increased CSF IgM levels and molecules related to both B-cell immunity (IL-10) and recruitment (CXCL13 and CCL21) and to macrophage/microglia activity (IL-12p70, CX3CL1, and CHI3L1) suggests possible correlation between humoral and innate intrathecal immunity in early disease stage. Furthermore, the association of IgM levels with WMLs and MS clinical and MRI activity after 2 years supports the idea of key role of IgM in the disease course.

Analysis of peripheral blood lymphocyte phenotype and function during dexamethazone treatment of progressive multiple sclerosis

Five patients with chronic progressive multiple sclerosis (MS) and three control patients with lumbar disc herniation were treated with dexamethazone during 14 days. The effect on peripheral blood T-cell subsets and on the proliferative response of peripheral blood mononuclear cells (PBMC) to pokeweed mitogen (PWM) and anti-mu antibody was analyzed. Before treatment, the proportion of CD3+ and CD4+ PBMC was similar in MS and control patients, but the proportion of CD8+ and DR+ PBMC was lower and the PBMC were less responsive to anti-mu stimulation in MS patients compared to controls. Steroid treatment induced reversible granulocytosis and lymphocytosis. CD3+ and CD4+ cells increased and DR+ cells decreased in MS patients but not in controls. Proliferation of anti-mu stimulated PBMC increased in MS-patients during the two weeks of treatment, but decreased in controls. The enhancement in the MS patients of pre-existing immune abnormalities suggests that a cautious attitude is warranted in the use of steroid treatment in chronic progressive MS.

Sensitive competitive-binding ELISAs for quantifying free kappa and lambda light chains in cerebrospinal fluid

Simple, sensitive, and fully standardized solid-phase enzyme-linked competitive binding immunoassays to quantify free kappa and lambda immunoglobulin light chains are described. The assays were developed to measure the concentration of free light chains in cerebrospinal fluid (CSF), in part because elevated levels of free kappa light chains have utility as a diagnostic marker for multiple sclerosis (MS). Polyclonal rabbit antibodies raised against pooled Bence Jones proteins are bound to solid-phase Staphylococcal protein A and used as the primary antisera in this assay. A pool of Bence Jones proteins isolated from the urine of 10 individuals with multiple myeloma are used as a biotin-labeled ligand and to develop a standard curve. The assays as described are sensitive to the low nanogram range and are specific for free kappa or lambda light chains. The assays were found to have acceptable precision, and results correlated highly with concentrations determined using competitive-binding radioimmunoassays previously described.

Antibodies to myelin basic protein and measles virus in multiple sclerosis: precursor frequency analysis of the antibody producing B cells

Antibody-producing B lymphocytes were polyclonally activated and transformed, by Epstein-Barr virus (EBV), into multiple B lymphoblastoid cell lines in a microculture system. The frequencies of B precursor cells producing antibodies to myelin basic protein (MBP) and measles virus were analyzed in peripheral blood of patients with multiple sclerosis (MS) and control subjects. Measles virus-specific B cells were detected at a significantly higher frequency in MS patients (n = 10, P less than 0.005) than patients with other neurological diseases (n = 10) and normal subjects (n = 10). In contrast, the frequencies of B cells producing anti-MBP antibodies and natural antibodies did not differ statistically among the three groups tested (P greater than 0.05). In addition, the anti-MBP antibodies produced by a panel of stable B cell lines obtained were found to react selectively with an epitope(s) within the C-terminal half fragment 90-171 of the human MBP molecule. In our experiments, no antibody cross-reactivity between MBP and measles virus could be detected in a total of 2760 B cell cultures.