Chlamydia trachomatis infection as a cause of pneumonia after human marrow transplantation.

Seventy-two marrow transplant patients were studied to assess the role of Chlamydia trachomatis infection in the etiology of pneumonia in the compromised host. Sixty-four patients had pneumonia from various causes and eight died of causes other than pneumonia. Chlamydial serologies and cultures of lung tissue, or other sites, or both, were obtained from all patients. C trachomatis was recovered from a single sputum specimen obtained at the onset of pneumonia in one patient, and three patients developed sustained IgG and IgM antibody responses to chlamydiae during their pneumonia. Two of the four patients died of pneumonia. These data further confirm that C trachomatis infection occurs in immunosuppressed patients in association with pneumonia. The source of the organism and the frequency of infection remain to be determined.