Immunophenotypic characterization of CSF B cells in virus-associated neuroinflammatory diseases

Intrathecal antibody synthesis is a well-documented phenomenon in infectious neurological diseases as well as in demyelinating diseases, but little is known about the role of B cells in the central nervous systems. We examined B cell and T cell immunophenotypes in CSF of patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) compared to healthy normal donors and subjects with the other chronic virus infection and/or neuroinflammatory diseases including HIV infection, multiple sclerosis (MS) and progressive multifocal leukoencephalopathy. Antibody secreting B cells (ASCs) were elevated in HAM/TSP patients, which was significantly correlated with intrathecal HTLV-1-specific antibody responses. High frequency of ASCs was also detected in patients with relapsing-remitting multiple sclerosis (RRMS). While RRMS patients showed significant correlations between ASCs and memory follicular helper CD4+ T cells, CD4+CD25+ T cells were elevated in HAM/TSP patients, which were significantly correlated with ASCs and HTLV-1 proviral load. These results highlight the importance of the B cell compartment and the associated inflammatory milieu in HAM/TSP patients where virus-specific antibody production may be required to control viral persistence and/or may be associated with disease development

Correlation between ASC and CD4⁺ T cell subsets.

<p>(A) Correlation of ASCs with memory Tfh cells in CSF of patients with MS, HAM/TSP, HIV and PML using Spearman’s rank correlation test. (B) Correlation of ASCs with CD4⁺CD25⁺ T cells in CSF of patients with HAM/TSP and PML using Spearman’s rank correlation test. (C) Comparison of frequency of CD4⁺CD25⁺ T cells and ASCs in CSF of HAM/TSP patients between non-progressors and progressors using Mann-Whitney Test. The horizontal line represents the mean. (D) Correlation of ASCs in CSF B cells with disease duration in HAM/TSP patients (n = 32) using Spearman’s rank correlation test.</p

Detection of antibody secreting B cells in CSF.

<p>Detection of antibody secreting B cells in CSF.</p

Detection of memory Tfh cells in CSF of chronic virus infection and/or neuroinflammatory diseases.

<p>(A) Detection of memory Tfh cells in peripheral blood and CSF. Representative dot plots of memory Tfh cells (CXCR5⁺ CD45RA^-; red rectangles) in CD4⁺ T cells and PD-1 expression in memory Tfh cells of peripheral blood and CSF of a ND and a HAM/TSP patient. (B) Comparison of frequency of memory Tfh cells in CSF using Kruskal-Wallis test with Dunn’s test. The horizontal line represents the mean. (C) Comparison of frequency of memory Tfh cells in peripheral blood using Kruskal-Wallis test with Dunn’s test. The horizontal line represents the mean.</p

Antibody responses against HTLV-1 in CSF of HTLV-1-infected subjects.

<p>(A) Comparison of antibody responses against HTLV-1 Gag, Env and Tax in serum and CSF of ACs and HAM/TSP patients using Mann-Whitney Test. (B) Comparison of CSF/serum anti-HTLV-1 Gag, Env and Tax antibody ratio of HAM/TSP patients and ACs using Paired T test or Mann-Whitney Test. All the data were obtained from HAM/TSP patients (n = 44) and ACs (n = 4). The horizontal line represents the mean. (C) Correlation of ASCs in CSF B cells with anti-Gag, anti-Env and anti-Tax antibody index in HAM/TSP patients (n = 11) using Spearman’s rank correlation test.</p

Detection of CD4⁺CD25⁺ T cells in CSF of chronic virus infection and/or neuroinflammatory diseases.

<p>(A) Comparison of frequency of CD4⁺CD25⁺ T cells in CSF using Kruskal-Wallis test with Dunn’s test. The horizontal line represents the mean. (B) Comparison of frequency of CD4⁺CD25⁺ T cells in peripheral blood using Kruskal-Wallis test with Dunn’s test. The horizontal line represents the mean. (C) Comparison of frequency of FoxP3 in peripheral blood CD4⁺CD25⁺ T cells using Kruskal-Wallis test with Dunn’s test. The horizontal line represents the mean. (D) Comparison of frequency of CTLA-4 in peripheral blood CD4⁺CD25⁺ T cells using Kruskal-Wallis test with Dunn’s test. The horizontal line represents the mean.</p

Detection of B cells in CSF of chronic virus infection and/or neuroinflammatory diseases.

<p>(A) Comparison of frequencies of B cells (left) and B cell/monocyte ratio (right) in CSF using Kruskal-Wallis test with Dunn’s test. The horizontal line represents the mean. (B) Detection of ASCs subset in B cells of CSF. (Left) Representative dot plots of IgD and CD27 staining in CSF CD19⁺ B cells of a ND and a HAM/TSP patient. IgD^- CD27⁺⁺ subsets (red rectangles) represent ASCs. (C) Comparison of frequencies of ASCs (left) and absolute number of ASCs (right) in CSF using Kruskal-Wallis test with Dunn’s test. The horizontal line represents the mean.</p