Cytomegalovirus primary infection in a patient with multiple sclerosis treated with alemtuzumab.

Alemtuzumab is an anti-CD52 monoclonal antibody approved for the treatment of multiple sclerosis (MS). It produces rapid depletion of T and B lymphocytes, which could predispose to opportunistic infections. We report one patient with MS who develops cytomegalovirus (CMV) primary infection after a third cycle of alemtuzumab, with spontaneous recovery associated with rapid lymphocyte reconstitution.