Tubal factor pathology caused by Chlamydia trachomatis:: the role of serology

One of the causes of infertility in females is tubal pathology as a result of pelvic inflammatory disease (PID) caused by Chlamydia trachomatis (Ct). Diagnosis and identification of patients is hampered by the lack of rapid, easy, sensitive and specific methods. The introduction of Ct-specific enzyme-linked immunosorbent assay (ELISA) tests, based upon synthetic peptides may subsequently increase the sensitivity and specificity for the detection of tubal factor infertility caused by Ct. In order to determine the value of these tests for serological diagnosis of Ct infections, we evaluated several commercially available assays (C. trachomatis enzyme immunoassay (EIA), Labsystems (CtL); SeroCT, Savyon (CtS); pELISA, Medac (CtMp); and a reference assay rELISA, Medac (CtMr)) in two study populations. The first group consisted of 134 female patients with infertility problems. Tubal factor infertility was observed in 85 of these patients (63%). A higher % positivity was found for Ct-specific IgG for the CtL, CtS and CtMp, 41% vs 10%, 57% vs 18% and 55% vs 25% respectively as compared to patients with infertility due to other problems. A similar trend was observed for Ct-specific IgA. The specificity of Ct-specific IgA and IgG in this patient group varied between 92 to 98% and 76 to 90%, respectively. The second group consisted of 107 consecutive gynaecology patients with fertility problems or suspected PID. In this particular patient group, the specificity of the peptide based tests wore around 80% and 90% for Ct-specific IgA and 75% and 85% for Ct-specific IgG, respectively. The negative predictive values exceeded 90%, while the positive predictive values varied from 30% to 47% for Ct-specific IgA and was around 30% for Ct-specific IgG. Testing Ct-specific IgG had no additional value above Ct-specific IgA alone. We conclude that the new synthetic peptide-based EIA tests are able to detect species-specific antibodies, which are correlated to (active) infection, and that in particular IgA may be useful in the serodiagnosis of tubal factor infertility caused by C. trachomatis, and will contribute in simplifying the work-up in patients with infertility.