Late-onset acute haemorrhagic necrotizing granulomatous adenovirus tubulointerstitial nephritis in a renal allograft

(Section Editor: A. Meyrier) Adenovirus (AV) is a relatively common infection in solid organ transplant recipients, and has a wide clinical presentation and outcome, ranging from subclinical and self-limiting to lethal disease. In renal transplant patients, symptomatic AV infection presents with tubulointerstitial nephritis, acute haemorrhagic cystitis, pneumonia or fatal disseminated viral disease. Most often, AV infection occurs within weeks to months after transplantation, suggesting reactivation of a latent AV in the immunosuppressed recipient as the source of infection. This report describes an unusual case of AV infection in the native lung but also in the renal allograft, 12 years after transplantation. The patient presented with gross haematuria, pain over the kidney allograft, fever and acute renal failure. The late onset of infection suggested de novo infection in an immunosuppressed patient rather than activation of latent infection or donor-origin infection. Renal biopsies showed severe haemorrhagic necrotizing granulomatous tubulointerstitial nephritis. Viral cytopathic changes were present in tubular epithelial cell nuclei, but since the more common polyomavirus immunostaining was negative, a diagnosis of viral infection was not made at the time. The late onset of infection, the presence of a well-defined granulomatous reaction, and the under recognition of adenovirus infection made the clinicopathological diagnosis difficult.