In contrast to natalizumab, another integrin-targeting antibody for the treatment of multiple sclerosis, which may induce multifocal leukoencephalopathy (PML) [38,39], in patients previously exposed to polyomavirus 2, no vulnerability towards viral infections was reported after CD18 antibodies. The gene discussed is ITGB2; the disease is progressive multifocal leukoencephalopathy.