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 ha ve a higher prevalence of the disease than women. Methods-The number and specificity of the antibody responses to 27 differen t C trachomatis antigens were determined by western blots in serum samples from patients with C trachomatis urogenital infection, with and without rea ctive arthritis, with a special regard to the sex of the patients. Results-Patients with reactive arthritis had antibodies to significantly fe wer chlamydia antigens than those with urethritis only. Antibodies from men recognised significantly fewer antigens than antibodies from women. The Ig A class antibodies were slightly more relevant than those of the IgG class for differentiation of patients with reactive arthritis from those with unc omplicated genitourinary infection. Conclusions-In patients with acute C trachomatis infection the development of reactive arthritis may be related, particularly in men, to a deficient h umoral response, to antigens which perhaps play a part in the clearance of the bacteria. Men who cannot generate antibodies to a large number of antig ens may be less able to contain the local infection, allowing a wide system ic dissemination of the organisms to the joints.