Multiple sclerosis (PP-038) (original) (raw)

we analysed B cells (immature, naïve, marginal-zone-like, IgM only and switched memories B cells) in non-treated patients presenting with a first demyelinating episode (CIS) and relapsing-remitting (RR)-MS. Immature B cells appeared to be dramatically reduced in the circulating compartment of both patients groups (5.5-and 3.7-fold respectively). We postulated a pathogenic tissue-specific recruitment of these cells. Thus, we analysed the a4, b1 and b7 integrins expression by different B-cell subsets. In both basal and pathological conditions, immature B cells expressed highly a4 and b7. Interestingly, immature B cells from CIS and RR-MS groups up-regulated b1. Patients treated with an anti-4 (Natalizumab), which block leukocytes recruitment to the CNS, showed normal immature B-cell proportions. Therefore, immature B cells might be involved in disease development by their ability to cross the inflamed blood-brain-barrier. Immature B cells are not primed; therefore, antigen-dependent activation of B cells might also occur inside the CNS.