Male sex predominance in Chlamydia trachomatis sexually acquired reactive arthritis: are women more protected by anti-chlamydia antibodies?

OBJECTIVE To determine whether the humoral anti-chlamydia antibody response might be related to the ineffective bacterial elimination seen in patients with Chlamydia trachomatis reactive arthritis, particularly in men, who have a higher prevalence of the disease than women. METHODS The number and specificity of the antibody responses to 27 different C trachomatis antigens were determined by western blots in serum samples from patients with C trachomatis urogenital infection, with and without reactive arthritis, with a special regard to the sex of the patients. RESULTS Patients with reactive arthritis had antibodies to significantly fewer chlamydia antigens than those with urethritis only. Antibodies from men recognised significantly fewer antigens than antibodies from women. The IgA class antibodies were slightly more relevant than those of the IgG class for differentiation of patients with reactive arthritis from those with uncomplicated genitourinary infection. CONCLUSIONS In patients with acute C trachomatis infection the development of reactive arthritis may be related, particularly in men, to a deficient humoral response, to antigens which perhaps play a part in the clearance of the bacteria. Men who cannot generate antibodies to a large number of antigens may be less able to contain the local infection, allowing a wide systemic dissemination of the organisms to the joints.