Primary dapsone chemoprophylaxis for Pneumocystis carinii pneumonia in immunocompromised patients infected with the human immunodeficiency virus.

During a 12-month period from August 1, 1986 to July 31, 1987, a study of primary chemoprophylaxis with dapsone for Pneumocystis carinii pneumonia was undertaken in immunodeficient patients who were infected with the human immunodeficiency virus. One attack of P. carinii pneumonia occurred among 16 patients who received chemoprophylaxis immediately that a T-helper (CD4) lymphocyte count of less than 0.2 x 10(9)/L was recorded compared with 16 attacks in the historical control group of 46 similar patients who did not receive chemoprophylaxis (log-rank test, chi 2(1) = 3.72; P = 0.05).