An Outbreak of Community-Acquired<i>Pneumocystis carinii</i>Pneumonia

TLDR

Eleven community‑acquired Pneumocystis carinii pneumonia cases were identified between 1979 and 1981, prompting clinical and immunologic evaluation. The cohort comprised young men who were drug abusers, homosexuals, or both, all presenting with pneumonia. Immunologic testing revealed depressed lymphocyte counts and proliferation with intact humoral immunity; among the 11 patients, one had Kaposi's sarcoma, another angioimmunoblastic lymphadenopathy, eight died, and the remaining three had persistent immune defects without a diagnosed immunosuppressive disease, underscoring the critical role of cell‑mediated immunity and the high risk for drug abusers and homosexuals. Published in the New England Journal of Medicine, 1981; 305:1431–8.

Abstract

Eleven cases of community-acquired Pneumocystis carinii pneumonia occurred between 1979 and 1981 and prompted clinical and immunologic evaluation of the patients. Young men who were drug abusers (seven patients), homosexuals (six), or both (two) presented with pneumonia. Immunologic testing revealed that absolute lymphocyte counts, T-cell counts, and lymphocyte proliferation were depressed, and that humoral immunity was intact. Of the 11 patients, one was found to have Kaposi's sarcoma, and another had angioimmunoblastic lymphadenopathy. Eight patients died. In the remaining three, no diagnosis of an immunosuppressive disease was established, despite persistence of immune defects. These cases of pneumocystosis suggest the importance of cell-mediated immune function in the defense against P. carinii. The occurrence of this infection among drug abusers and homosexuals indicates that these groups may be at high risk for this infection. (N Engl J Med. 1981; 305:1431–8.)