BK virus as the cause of meningoencephalitis, retinitis and nephritis in a patient with AIDS

Background: The two widely spread human polyomaviruses, BK virus (BKV) and JC virus (JCV) establish latency in the urinary tract, and can be reactivated in AIDS. JCV might cause progressive multifocal leucoencephalopathy, but although up to 60% of AIDS patients excrete BKV in the urine there have been few reports of BKV-related renal and/or neurological disease in AIDS. Objective: To report on an AIDS patient with progressive renal and neurological symptoms involving the retina. Design: Case report. Setting: Venhalsan, Soder Hospital, Stockholm, Sweden. Methods: The brain, eye tissue, cerebrospinal fluid, urine and peripheral blood mononuclear cells were analysed by nested PCR for polyoma-virus DNA. Macroscopical and microscopical examination were performed of the kidney and brain post mortem. Immunohistochemical stainings for the two BKV proteins, the VP1 and the agnoprotein, were performed on autopsy material and virus infected tissue culture cells. Results: BKV could be demonstrated in the brain, cerebrospinal fluid, eye tissues, kidneys and peripheral blood mononuclear cells. Conclusion: During 6years, approximately 400 cerebrospinal fluid samples from immunosuppressed individuals with neurological symptoms have been investigated by PCR for the presence of polyomaviruses. BKV DNA has, so far, only been found in the case reported here. Although reports of BKV infections in the nervous system are rare, there is now evidence for its occurrence in immunocompromised patients and the diagnosis should be considered in such patients with neurological symptoms and signs of renal disease. The diagnosis is simple to verify and is important to establish.