Ocrelizumab for Post-Alemtuzumab Paradoxical Disease Activity in Highly Active Multiple Sclerosis.

Alemtuzumab is a humanized anti-CD52 antibody that is registered for treatment of highly active relapsing-remitting multiple sclerosis. Disease activity after alemtuzumab treatment is infrequent. It may be a result of lack of lymphocyte depletion due to development of neutralizing autoantibodies. On the other hand, severe disease activity has been described after alemtuzumab, which is suggested to be caused by B-cell hyperpopulation. We present a case of a person with multiple sclerosis with severe disease activation after alemtuzumab administration that may represent paradoxical B cell-mediated disease activity. The patient was successfully treated with ocrelizumab.