Serum IgG1 and IgG3 Antibody Responses to Chlamydia trachomatis Pgp3 and Hsp60 in Tubal Factor Infertility.

Abstract

Our goal was to investigate IgG1 and IgG3 antibody responses to Chlamydia trachomatis proteins Pgp3 and Hsp60 in women with tubal factor infertility (TFI). Our goal was to determine the role of these biomarkers in the diagnosis of C. trachomatis-associated TFI, and assess their sensitivity and specificity for detecting tubal pathology. Serum samples were collected from 258 subfertile women, and 34 women positive for C. trachomatis by nucleic acid amplification test (NAAT). IgG1 and IgG3 antibodies to Pgp3 and Hsp60 were measured using enzyme immune assays. Pgp3 IgG1 antibodies were detected in 68.2% of TFI cases and 31.8% of controls (non-TFI), while Hsp60 IgG1 antibodies were found in 36.4% of TFI cases. Pgp3 IgG1 had the highest sensitivity for TFI (68.2%; 95% confidence interval [CI], 45.1%-86.1%), while Hsp60 IgG3 was the most specific (93.6%; 95% CI, 89.7-96.4). Antibody levels increased with tubal damage severity. Among the 34 NAAT-positive women, 78.8% were positive for Pgp3 IgG1. Pgp3 IgG1 antibody was a sensitive marker for detecting C. trachomatis-related TFI, while Hsp60 IgG3 antibody was highly specific. These findings suggest that Pgp3 and Hsp60 antibodies and antibody subclass testing may be useful diagnostic tools for assessing TFI.