Which one of the following drugs is the most common cause of progressive multifocal leukoencephalopathy?: (A) Natalizumab, (B) Cituximab, (C) Rituximab, (D) Bevacizumab
Answer is A. Causes of progressive multifocal leukoencephalopathy:AIDSHematological malignanciesTransplant recipientsChronic inflammatory diseasesNatalizumab, a humanized monoclonal antibody(ref:Harrison's 18/e p3427)