Bacterial and CMV pneumonia in a patient treated with alemtuzumab for multiple sclerosis.

Alemtuzumab (a drug highly active in multiple sclerosis) is a humanized monoclonal antibody targeting the surface molecule CD52. It causes a rapid depletion of innate and adaptive immune cells with a peak during the first month after infusion. Infection rates in alemtuzumab-treated patients with multiple sclerosis in clinical trials were higher in than in interferon beta-treated patients. Cytomegalovirus (CMV) primary infections and reactivations have been reported in this setting of patients. We describe the case of a patient that developed both viral (CMV) and bacterial pneumonia one month after alemtuzumab infusion for multiple sclerosis. Physicians dealing with this drug should be aware of this serious but treatable complication.