No lack of regulatory B cells in patients with Multiple Sclerosis

International audienc

Unaltered regulatory B-cell frequency and function in patients with multiple sclerosis

International audienceMultiple sclerosis (MS) is a chronic disease of the central nervous system (CNS) typically characterized by the recruitment of T cells into the CNS. However, certain subsets of B cells have been shown to negatively regulate autoimmune diseases and some data support a prominent role for B cells in MS physiopathology. For B cells in MS patients we analyzed subset frequency, cytokine secretion ability and suppressive properties. No differences in the frequencies of the B-cell subsets or in their ability to secrete cytokines were observed between MS and healthy volunteers (HV). Prestimulated B cells from MS patients also inhibited CD4 + CD25 − T cell proliferation with a similar efficiency as B cells from HV. Altogether, our data show that, in our MS patient cohort, regulatory B cells have conserved frequency and function

Increased risk of multiple sclerosis relapse after in vitro fertilisation

Michel, Laure Foucher, Yohann Vukusic, Sandra Confavreux, Christian de Seze, Jerome Brassat, David Clanet, Michel Clavelou, Pierre Ouallet, Jean-Christophe Brochet, Bruno Pelletier, Jean Labauge, Pierre Lebrun, Christine Lepage, Emmanuelle Le Frere, Fabienne Jacq-Foucher, Marylene Barriere, Paul Wiertlewski, Sandrine Laplaud, David-Axel Club Francophone de la Sclerose En Plaques (CFSEP) Research Support, Non-U.S. Gov't England Journal of neurology, neurosurgery, and psychiatry J Neurol Neurosurg Psychiatry. 2012 Aug;83(8):796-802. Epub 2012 Jun 11.BACKGROUND: Exogenous sexual steroids together with pregnancy have been shown to influence the risk of relapses in multiple sclerosis (MS). Treatments used during assisted reproductive techniques may consequently influence the short term evolution of MS by modifying the hormonal status of the patient. The objective of this study was to determine if there was an increased risk of developing exacerbations in women with MS after in vitro fertilisation (IVF). METHODS: MS and IVF data were either automatically extracted from 13 French university hospital databases or obtained from referring neurologists. After matching databases, patient clinical files were systematically reviewed to collect information about MS and the treatments used for IVF. The association between IVF and the occurrence of MS relapses was analysed in detail using univariate and multivariate statistical tests. FINDINGS: During the 11 year study period, 32 women with MS had undergone 70 IVF treatments, 48 using gonadotrophin releasing hormone (GnRH) agonists and 19 using GnRH antagonists. A significant increase in the annualised relapse rate (ARR) was observed during the 3 month period following IVF (mean ARR 1.60, median ARR 0) compared with the same period just before IVF (mean ARR 0.80, median ARR 0) and to a control period 1 year before IVF (mean ARR 0.68, median ARR 0). The significant increase in relapses was associated with the use of GnRH agonists (Wilcoxon paired test, p=0.025) as well as IVF failure (Wilcoxon paired test, p=0.019). INTERPRETATION: An increased relapse rate was observed in this study after IVF in patients with MS and may be partly related both to IVF failure and the use of GnRH agonists

Characterization of antigen-specific B cells using nominal antigen-coated flow-beads.

In order to characterize the reactivity of B cells against nominal antigens, a method based on the coupling of antigens onto the surface of fluorescent core polystyrene beads was developed. We first demonstrate that murine B cells with a human MOG-specific BCR are able to interact with MOG-coated beads and do not recognize beads coated with human albumin or pp65. B cells purified from human healthy volunteer blood or immunized individuals were tested for their ability to interact with various nominal antigens, including viral, vaccine, self and alloantigens, chosen for their usefulness in studying a variety of pathological processes. A substantial amount of B cells binding self-antigen MOG-coated beads can be detected in normal blood. Furthermore, greater frequencies of B cell against anti-Tetanic Toxin or anti-EBNA1 were observed in primed individuals. This method can reveal increased frequencies of anti-HLA committed B cells in patients with circulating anti-HLA antibodies compared to unsensitized patients and normal individuals. Of interest, those specific CD19 cells were preferentially identified within CD27(-)IgD(+) (i-e naïve) subset. These observations suggest that a broad range of medical situations could benefit from a tool that allows the detection, the quantification and the characterization of antigen-specific blood B cells

Neuropathologic, phenotypic and functional analyses of Mucosal Associated Invariant T cells in Multiple Sclerosis

International audienceBackground: The involvement of Mucosal Associated Invariant T (MAIT) cells, which are anti-microbial semi-invariant T cells, remains elusive in Multiple Sclerosis (MS).Objective: Deciphering the potential involvement of MAIT cells in the MS inflammatory process. Methods: By flow cytometry, blood MAIT cells from similar cohorts of MS patients and healthy volunteers (HV) were compared for frequency, phenotype, activation potential after in vitro TCR engagement by bacterial ligands and transmigration abilities through an in vitro model of blood-brain barrier. MS CNS samples were also studied by immunofluorescent staining and quantitative PCR.Results and conclusion: Blood MAIT cells from relapsing-remitting MS patients and HV presented similar frequency , ex vivo effector phenotype and activation abilities. MAIT cells represented 0.5% of the total infiltrating T cells on 39 MS CNS lesions. This is low as compared to blood frequency (p b 0.001), but consistent with their low trans-migration rate. Finally, transcriptional over-expression of MR1-which presents cognate antigens to MAIT cells-and of the activating cytokines IL-18 and IL-23 was evidenced in MS lesions, suggesting that the CNS microenvi-ronment is suited to activate the few infiltrating MAIT cells. Taken together, these data place MAIT cells from MS patients as minor components of the inflammatory pathological process

An intermediate level of CD161 expression defines a novel activated, inflammatory, and pathogenic subset of CD8+ T cells involved in multiple sclerosis

International audienceSeveral lines of evidence support a key role for CD8+ T cells in central nervous system tissue damage of patients with multiple sclerosis. However, the precise phenotype of the circulating CD8+ T cells that may be recruited from the peripheral blood to invade the CNS remains largely undefined to date. It has been suggested that IL-17 secreting CD8 (Tc17) T cells may be involved, and in humans these cells are characterized by the expression of CD161. We focused our study on a unique and recently described subset of CD8 T cells characterized by an intermediate expression of CD161 as its role in neuroinflammation has not been investigated to date. The frequency, phenotype, and function of CD8+ T cells with an intermediate CD161 expression level were characterized ex-vivo, in vitro, and in situ using RNAseq, RT-PCR, flow cytometry, TCR sequencing, and immunohistofluorescence of cells derived from healthy volunteers (n = 61), MS subjects (n = 90), as well as inflammatory (n = 15) and non-inflammatory controls (n = 6). We report here that CD8+CD161int T cells present characteristics of effector cells, up-regulate cell-adhesion molecules and have an increased ability to cross the blood-brain barrier and to secrete IL-17, IFNγ, GM-CSF, and IL-22. We further demonstrate that these cells are recruited and enriched in the CNS of MS subjects where they produce IL-17. In the peripheral blood, RNAseq, RT-PCR, high-throughput TCR repertoire analyses, and flow cytometry confirmed an increased effector and transmigration pattern of these cells in MS patients, with the presence of supernumerary clones compared to healthy controls. Our data demonstrate that intermediate levels of CD161 expression identifies activated and effector CD8+ T cells with pathogenic properties that are recruited to MS lesions. This suggests that CD161 may represent a biomarker and a valid target for the treatment of neuroinflammation

Enhanced frequency of anti-HLA B cell in immunized patients.

<p><b>A.</b> Using single HLA-A*0201 coated beads, the frequency of B cells specific to HLA-A*0201 allele was assessed in the blood of sensitized transplant recipients with histologically proven antibody mediated rejection (ABMR; n = 10), non-sensitized stable transplant recipients (n = 9) and healthy volunteers (n = 14). Sensitized patients exhibit a significant increase in the frequency of HLA-A*0201 specific B cells compared to non-sensitized patients and healthy volunteers. p value are mentioned (Kruskall-Wallis follow by a Dunn’s post hoc test) <b>B.</b> B cells bound to single HLA class I coated beads (HLA-beads), to negative control (NC) and positive control (PC) were analyzed in HV (n = 16) and Immunized kidney recipients (n = 13). NC and PC beads were included by the manufacture in the single HLA class I kit. According to the manufacture, NC beads are beads saturated with ovalbumin and PC beads are coated with human IgG1. A broad range of single HLA class I were recognized as shown in the insert, a pattern observed for B cells from all tested patients. p value is indicated (Mann-Whitney test).</p

B cells from healthy volunteers exhibit a broad range of reactivity.

<p>Purified B cells from healthy volunteers were tested for their reactivity to albumin (n = 38), Tetanus Toxin (n = 14), EBNA1 (n = 15), MOG_1–125 (n = 38) and a panel of 97 HLA class I molecules (n = 19). ***p<0.001 (Kruskall-Wallis follow by a Dunn’s post hoc test using albumin settings as reference group).</p