A Cluster ofPneumocystis cariniiPneumonia in Adults without Predisposing Illnesses

PNEUMOCYSTIS CARINII pneumonia is the most common infection complicating the acquired immunodeficiency syndrome (AIDS),1 , 2 but before 1981 it was a rare condition. P. carinii pneumonia was first reported in the United States in 1955,3 and only 107 cases were reported during the subsequent decade.4 Before the AIDS epidemic, more than 99 percent of patients with P. carinii pneumonia had a predisposing condition, such as lymphoma, leukemia, organ transplantation, or a disorder treated with corticosteroids or cytotoxic drugs.4 , 5 Reports of P. carinii pneumonia in nonimmunocompromised adults are extremely rare.6 7 8 9 10 Serologic but not histopathological evidence of latent subclinical P. carinii infection has . . .