Disseminated Pneumocystis carinii infection causing extrapulmonary organ failure: clinical, pathologic, and immunohistochemical analysis.

Pneumocystis carinii pneumonia is an important infection in the immunocompromised host, and the rate of symptomatic infections has risen dramatically with the advent of immunosuppressive therapies and infections with the human immunodeficiency virus (HIV). However, dissemination of P. carinii is thought to be an unusual event, and it is rarely suspected of causing extrapulmonary symptomatology. We have recently examined the cases of patients with acquired immunodeficiency syndrome (AIDS) who demonstrated at autopsy extrapulmonary infection with P. carinii. Three of these patients had widespread pneumocystosis, and in one patient dysfunction in several organs could be directly attributed to effects of P. carinii, which contributed to his death. The possible factors leading to dissemination of P. carinii are discussed. We also describe the use of a newly developed monoclonal antibody to P. carinii in detecting extrapulmonary infections.