# Serum IgG1 and IgG3 Antibodies to Chlamydia trachomatis Pgp3 and Hsp60 in Men of Subfertile Couples

## TL;DR

This study found that antibodies to Chlamydia trachomatis proteins in men may be linked to reduced sperm motility and shape, suggesting a possible link between past infection and male infertility.

## Contribution

The study identifies a novel association between Chlamydia trachomatis Pgp3 antibodies and impaired sperm motility in subfertile men.

## Key findings

- Pgp3 IgG1 and IgG3 antibodies were associated with impaired sperm motility in subfertile men.
- Hsp60 IgG1 antibodies were linked to a higher teratozoospermia index.
- The association between Pgp3 IgG1 and asthenozoospermia remained significant after adjusting for lifestyle factors.

## Abstract

Our goal was to investigate immunoglobulin G1 (IgG1) and immunoglobulin G3 (IgG3) antibody responses to Chlamydia trachomatis proteins Pgp3 and Hsp60 in males of subfertile couples and to explore the association of these antibodies with semen parameters and male factor infertility.

Serum samples were collected from 256 male partners of subfertile couples. Serum IgG1 and IgG3 antibodies to C trachomatis Pgp3 and Hsp60 were measured using enzyme immunoassays. Semen samples were analyzed for volume, sperm concentration, and motility according to World Health Organization criteria.

Altogether, 74 (29.8%) men were seropositive to either C trachomatis Pgp3 IgG1 or IgG3, and 67 (27.0%) to either Hsp60 IgG1 or IgG3. Chlamydia trachomatis Pgp3 IgG1 and IgG3 antibodies were associated with impaired sperm motility (asthenozoospermia) (18.6% vs 6.3%, P = .006 for Pgp3 IgG1; and 21.4% vs 8.0%, P = .03 for Pgp3 IgG3). After adjusting for smoking, alcohol risk consumption, and body mass index, the association between serum C trachomatis Pgp3 IgG1 seropositivity and asthenozoospermia remained statistically significant (odds ratio, 3.0 [95% confidence interval, 1.12–8.01]; P = .03). The presence of Hsp60 IgG1 antibody was associated with a higher teratozoospermia index (1.47 ± 0.15 vs 1.39 ± 0.16; P = .001).

Our results suggest that prior Chlamydia trachomatis infection, as indicated by Pgp3 seropositivity, may negatively impact male fertility potential by affecting sperm motility and morphology.

The study examined IgG1 and IgG3 antibody responses to Chlamydia trachomatis proteins Pgp3 and Hsp60 in subfertile men. The findings suggest that prior chlamydial infection may impair male fertility by adversely affecting sperm motility and morphology.