The investigators aim to longitudinally evaluate quantitative and functional changes in peripheral blood B-cell subsets (1) at the initiation phases of MS, i.e. radiological isolated syndrome (RIS) and clinically isolated syndrome (CIS) (2) during progression of MS and (3) between the two clinical forms of MS in naïve treatment patient: Relapsing-Remittent MS (RRMS) and Primary Progressive MS (PPMS). B-cell subsets are defined by a combination of membrane markers and enumerated at different time points (inclusion (before treatment) and at 3, 6, 12, 24 months of treatment initiation) in a whole blood flow cytometric (FCM) analysis. The absolute counts and relative proportions of transitional, naïve, memory, and marginal zone-like B-cell subsets are being followed up prospectively in patients with a radiologically isolated syndrome (RIS, n= 20), with clinically isolated syndrome (CIS, n= 20), in MS patients with relapsing remitting form (RRMS, n = 20) and in MS patients with primary progressive evolution of the disease (PPMS, n = 20). Control samples are being collected from patients affected by other inflammatory diseases with neurological symptoms (Devic syndrome, Neurobehcet, neurosarcoidosis n = 20) or without neurological symptoms (systemic sclerosis, SSc, n= 20) and from blood donors (n = 40). In order to evaluate functional properties of B cells, peripheral blood mononuclear cells (PBMC) from each group of patients are activated with CD40 ligand and CpG Oligodeoxynucleotides (CpG ODNs), and IL-10-producing B-cells are enumerated by FCM after a brief incubation with phorbol myristate acetate, ionomycin, and brefeldin A as a protein transport inhibitor agent. In selected CIS and MS patients whose changes in B-cell subpopulations associated with onset or progression of the disease are representative, the B-cell subpopulations will be purified and activated with CD40 ligand and CpG ODNs to be co cultured with anti-CD3-activated autologous T-cells to evaluate inhibitory or potentiating effects on T-cell production of pro-inflammatory cytokines (e.g. IFN-gamma, IL-17).