Male genital tract chlamydial infection: implications for pathology and infertility.

Chlamydia trachomatis infections are prevalent worldwide, but current research, screening, and treatment are focused on females, with the burden of disease and infertility sequelae considered to be a predominantly female problem. The prevalence of chlamydial infection, however, is similar in males and females. Furthermore, a role for this pathogen in the development of male urethritis, epididymitis, and orchitis is widely accepted. The role of Chlamydia in the development of prostatitis is controversial, but we suggest that Chlamydia is an etiological agent, with incidences of up to 39.5% reported in patients with prostatitis. Infection of the testis and prostate is implicated in a deterioration of sperm, possibly affecting fertility. Chlamydia infections also may affect male fertility by directly damaging the sperm, because sperm parameters, proportion of DNA fragmentation, and acrosome reaction capacity are impaired with chlamydial infection. Furthermore, the proportion of male partners of infertile couples with evidence of a Chlamydia infection is greater than that documented in the general population. An effect of male chlamydial infection on the fertility of the female partner also has been reported. Thus, the need for a vaccine to protect both males and females is proposed. The difficulty arises because the male reproductive tract is an immune-privileged site that can be disrupted, potentially affecting spermatogenesis, if inappropriate inflammatory responses are provoked. Examination of responses to infection in humans and in experimental animal models suggest that an immunoglobulin A-inducing vaccine will be able to target the male reproductive tract effectively while avoiding harmful inflammatory responses that may impair fertility.