Use of check-point inhibitors in the treatment of progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is an opportunist viral infection predominantly seen in immunosuppressed patients (most commonly in HIV cases, lymphoproliferative disorders and primary immunodeficiency) (1,2). This aggressive brain infection is caused by the JC virus (JCV), a DNV virus of the human polyomavirus family (3). Primary viremia is usually asymptomatic and occurs in childhood. After the primary infection, the virus remains in the body in a latent stage (4,5). The reactivation can be frequently following immunosuppression or after elimination of the B cells with drugs targeting B cells such a as monoclonal antibodies (mAb) (6).