Multiple sclerosis patients have peripheral blood CD45RO+ B cells and increased intestinal permeability

Abstract Background Recently, the success of anti-CD20 monoclonal antibody therapy brought a new light over the role of B cells in multiple sclerosis (MS) pathogenesis. Due to the expression pattern of CD20 during B cells ontogeny, this role seems to be extended beyond the antibodies' production and secretion. Therefore, here we investigated whether not only classical cytotoxic CD8+ T lymphocytes but also non-classical cytotoxic B cells may occur in the peripheral blood from relapsing-remitting MS (RRMS) patients. Methods 104 RRMS patients during different treatment and 58 healthy donors were studied. CD19, GzmB, Runx3 and CD49d expression was assessed by flow cytometry analyses. Results Patients treated with Natalizumab (NTZ) showed an increased percentage of CD8+GzmB+ when compared to other MS therapies, untreated RRMS patients and healthy volunteers. Similarly, and unexpected, massive cytotoxic behavior of B cells CD19+GzmB+ was observed in RRMS patients during Fingolimod (FTY) and NTZ therapies when compared to Glatiramer, Interferonβ, untreated MS patients and healthy donors. Conclusions During different MS treatments, B cells exhibit cytotoxic behavior resembling CD8+ T lymphocytes. This data suggest a possible involvement of “cytotoxic” B cells during MS pathology. Monitoring cytotoxic subsets might become an available marker for the risk of relapses and even for accessing therapeutic effectiveness in MS patients.

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Fingolimod alters intrathecal B cell maturation in multiple sclerosis patients

10.21203/rs.3.rs-23388/v1 ◽

2020 ◽

Author(s):

Markus C. Kowarik ◽

David Astling ◽

Gildas Lepennetier ◽

Alanna Ritchie ◽

Bernhard Hemmer ◽

...

Keyword(s):

Multiple Sclerosis ◽

B Cells ◽

B Cell ◽

Peripheral Blood ◽

Clonal Expansion ◽

Cell Maturation ◽

Lymphocyte Migration ◽

B Cell Maturation ◽

Natalizumab Treatment ◽

Multiple Sclerosis Patients

Abstract Background: B cells are postulated to play multiple roles in the pathogenesis of multiple sclerosis (MS) including pathogenic antibody production, antigen-presentation and pro-inflammatory cytokine secretion. Natalizumab and fingolimod are effective MS therapies that disrupt lymphocyte migration but exert differential effects on B cell maturation and trafficking. Herein, we investigated their effects on peripheral blood and cerebrospinal fluid (CSF) B cell repertoires.Methods: Paired CSF and peripheral blood (PB) lymphocytes were collected from MS patients at baseline and after 6 months of treatment with fingolimod (n = 4) or natalizumab (n = 4). B cell subsets including naïve, CD27+ memory, CD27-IgD- double-negative B cells and plasmablasts were collected by FACS and their respective heavy-chain variable region (VH) repertoires assessed by next generation deep sequencing (Illumina MiSeq).Results: Treatment with fingolimod lead to a distinct contraction of the PB B cell pool whereas natalizumab resulted in an expansion of circulating PB B cells. In contrast, CSF B cell numbers remained stable under treatment with fingolimod but decreased following natalizumab therapy. Clonal overlap between CSF and peripheral blood B cells was reduced following natalizumab treatment (-24% reduction of clonal groups) but remained stable with fingolimod therapy. Lineage analyses of CSF B cell repertoires at baseline and following therapy revealed large, clonally expanded B cell clusters in natalizumab-treated MS patients but no intrathecal clonal expansion following fingolimod therapy. Conclusions: Our findings suggest that natalizumab treatment diminishes the exchange of peripheral and intrathecal B cells but does not impact intrathecal clonal expansion. In contrast, fingolimod treatment fails to alter B cell exchange across the blood-brain-barrier but affects intrathecal clonal expansion. Sphingosine-1 phosphate receptor inhibition may impact MS disease progression by inhibiting intrathecal germinal center activity.

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