In the mid-1980s, physicians who examined many AIDS patients had the impression that a shift was occurring in the types and incidence of pulmonary complications associated with HIV infection. For example, there appeared to be an increased incidence of serious infections caused by pyogenic bacteria and pulmonary and extrapulmonary infection with M. tuberculosis had been noted with increased frequency. Furthermore, lymphoid interstitial pneumonitis (LIP), which is diagnostic of AIDS in children under 13 years old who are HIV antibody positive, was diagnosed with increased frequency in adults. Nonspecific interstitial pneumonitis also appeared to be on the rise. Legionella pneumonia, in contrast to its increased incidence during 1981-83, was now seldom encountered. However, apart from the increased incidence of tuberculosis, a reportable disease, these other shifts in the incidence of pulmonary complications had not been verified.