Pneumocystis carinii pneumonia: a cluster of eleven cases.

An unusual cluster of 11 patients with Pneumocystis carinii pneumonia occurred in a 3-month period at Memorial Hospital, New York. Ten of the 11 patients had lymphoma or leukemia. In 7 patients, corticosteroid therapy was decreased or stopped shortly before pneumocystis pneumonia was diagnosed. The pediatric patients had extensive contact in the outpatient department, and three of them had roomed together, suggesting the possibility of man to man transmission. Tree of 4 adult patients with Hodgkin's disease and pneumocystis pneumonia had the same physician. This physician had an indirect immunofluorescent titer of 1:16, as did an infectious disease resident involved in the care of 6 patients. Three of 9 patients tested showed indirect immunofluorescent titers of 1:16 or above, with rising or falling titers on serial specimens. Although definitive evidence of communicability was not established, patients with suspected or proved pneumocystis pneumonia are now isolated in this hospital.