Recurrent genital tract infections: a result of induced immunosuppression.

Many of the diseases commonly encountered in clinical practice may be considered as "recurrent", there being episodes of disease activity followed by variable periods of quiescence or low-grade activity. Although the aetiology ofmany of these conditions is unknown (for example, rheumatoid arthritis, ulcerative colitis, multiple sclerosis), certain infectious diseases are well known for their ability to recur. Interestingly, the genital tract appears particularly prone to recurrent disease. For example, true recurrence rather than reinfection has been well documented for herpes simplex virus (HSV) and human papillomavirus infection, candidiasis and nongonococcal urethritis. For the majority of patients recurrences are infrequent and pose few problems. However, a significant minority suffer frequent recurrences and experience severe physical and psychological morbidity. This article reviews various studies which have attempted to examine the immunopathogenesis of recurrent genital tract infection or which have suggested possible mechanisms to account for disease recurrence. Before detailing the various infections, however, it is important to note that the immune mechanisms operating at mucosal sites are somewhat different from those providing systemic immunity. Mucosal antibody secretion involves a complex system in which IgA predominates. The IgA in genital secretions (secretory IgA) is different from the IgA found in serum and is composed of a 10-S dimer, J chain, and a secretory component. The complexity of mucosal humoral immunity has been well reviewed by McNabb and Tomasi.' Mucosal cell-mediated immunity also exhibits certain unique characteristics. For example, the predominance of suppressor/ cytotoxic T lymphocytes in the genital tract contrasts with the pattern in lymphoid tissue where T-helper/ inducer lymphocytes outnumber suppressor cells.23