Remission of progressive

multifocal leucoencephalopathy in SLE after treatment with cidofovir: a 4 year follow up Progressive multifocal leucoencephalopathy (PML) is an opportunistic infection caused by human polyomaviruses such as the JC virus. It usually occurs as a severe complication of immunosuppression in patients with primary disorders of the immune system or secondary impairment of immune function, for exam-ple, after iatrogenic states of immunosup-pression. PML usually takes a rapidly progressive course and advances to death within 1 to 18 months. Today, PML is mainly seen in AIDS, while previously it was typically found in patients with granuloma-tous, neoplastic, or infectious diseases. In granulomatous diseases particularly, PML is thought to occur as a result of iatrogenic states of immunosuppression, but it is also seen in patients aggressively treated with immunosuppressive agents for systemic lupus erythematosus (SLE).1 2 PML pro-gresses to death in most of these patients even after withdrawing immunosuppressive therapy.2 Therefore additional therapy, aimed at supporting a more rapid restoration of immune function his warranted