Background: The anti-CD20 monoclonal antibody ocrelizumab has been widely employed in the treatment of people with multiple sclerosis (pwMS). However, its B-cell-depleting effect may induce a higher risk of infectious events and alterations in the secretion of B-cell-activating factors, such as BAFF, APRIL and CD40L. Methods: The aim of this study was to investigate plasma BAFF, APRIL and CD40L levels and their relationship with infectious risk in ocrelizumab-treated pwMS at baseline (T0), at 6 months (T6) and at 12 months (T12) after starting the treatment. As a control group, healthy donors (HD) were enrolled too. Results: A total of 38 pwMS and 26 HD were enrolled. At baseline, pwMS showed higher plasma BAFF (p p = 0.0223) and CD40L (p p p p = 0.0003 and p p p = 0.0056 and T12: p = 0.0400). Conclusions: BAFF may have a role as a marker of immune dysfunction and of infectious risk.
