Immunohistochemical demonstration of Chlamydial antigens in association with prostatitis.

The occurrence of Chlamydia trachomatis in association with histologically proven prostatitis was investigated. We used the immunoperoxidase technique with a monoclonal antibody against Chlamydia and evaluated formalin-fixed, paraffin-embedded sections from 16 cases of histologically proven prostatitis. Chlamydial antigens were detected within the prostate glands in 5 (31%) of these 16 cases. In contrast, none of 19 cases of prostatic hyperplasia without significant inflammation used as a control group showed staining for Chlamydia in the prostatic glands (P less than 0.03). Chlamydial antigens were, however, detected in the urothelium of the prostatic urethra in one of these control cases. Staining for Chlamydia occurred focally in atrophic glands and was associated with a predominantly chronic nonspecific inflammation. No cytoplasmic inclusions or other specific morphologic features of chlamydial infection could be identified on routine hematoxylin-eosin- or Giemsa-stained tissue sections from these specimens. Our results demonstrate that Chlamydia can infect the prostatic glands, and that its presence is statistically associated with marked nonspecific inflammation. We suggest that C. trachomatis may have an etiologic role in nonbacterial prostatitis.