Evidence of B-cell dysregulation in severe CNS inflammation after alemtuzumab therapy

Cases of severely exacerbated CNS inflammation have been described in patients with MS under treatment with alemtuzumab, a pan-lymphocyte– depleting anti-CD52 monoclonal antibody. On the basis of the peripheral lymphocyte subset network (higher B-cell and suppressed T-cell counts) and marked clinical improvement following plasmapheresis and rituximab treatment (anti-CD20 antibody), a B-cell–driven intrathecal autoimmune reaction was hypothesized.