Association of Positive Chlamydia trachomatis and Chlamydia pneumoniae Immunoglobulin G Titers with Increasing Age

Due to previously reported associations of ovarian cancer with pelvic inflammatory disease, tubal infertility, and positive Chlamydia trachomatis titers, women undergoing follow-up for ovarian cancer were screened with a C. trachomatis IgG titer. Positive titers were seen in 15 (79%) of 19 women with ovarian cancer, 9 (90%) of 10 age-matched controls, and 14 (67%) of 21 patients with infertility and pain. When analyzed by age, 4 (40%) of 10 women under 30 years of age and 34 (85%) of 40, 30 years of age or older had positive titers (p = 0.007). Of 21 women with positive Chlamydia pneumoniae titers, 17 (81%) had positive C. trachomatis titers, whereas 17 (85%) of 20 with positive C. trachomatis titers had positive C. pneumoniae titers. The high rate of positive C. trachomatis titers in older women may be due to cross-reaction with C. pneumoniae titers. Although C. trachomatis IgG titers may be useful as an immunologic screening marker in infertile women, the results of these tests should be interpreted with caution. A positive test may not be evidence of C. trachomatis infection and is not an indication for specific therapy.