Seroprevalence of antibodies to conserved regions of Chlamydia trachomatis heat shock proteins 60 and 10 in women in India

Persistent, untreated chlamydial infection causes chronic stimulation of the host immune system against immunogenic antigens such as chlamydial heat shock proteins (cHSP) 60 and 10. In order to find the seroprevalence of antibodies to cHSPs, enzyme-linked immunosorbent assay (ELISA) is performed using specific peptide sequences to measure antibody response against major outer membrane protein (MOMP), cHSP60 and cHSP10 in patient sera. In this study, 255 patients attending the gynaecology out-patient department (March 2004 to August 2005) of Safdarjung Hospital were enrolled. Of these patients, 107 were diagnosed with cervicitis while 52 had pelvic inflammatory disease (PID)/infertility. Chlamydia trachomatis infection in endocervical specimens is diagnosed by a direct fluorescence assay (DFA) and the polymerase chain reaction (PCR). In 75 (29.4%) of the C. trachomatis-positive women, 50 (66.7%) were ELISA positive for MOMP, 48 (64.0%) were positive for cHSP60 and 46 (61.3%) were positive for cHSP10. The anti-MOMP index correlated positively with anti-cHSP60 (R=0.522, P < 0.01) and anti-cHSP10 (R= 0.286, P < 0.05). Antibody titre for MOMP was significantly higher than that for cHSP60 (1:5; P < 0.01 and 1:25; P < 0.05). Moreover, patients with PID/infertility showed significantly higher antibody titres for cHSP60 and cHSP10 when compared to patients with cervicitis at dilutions of 1 in 50, 1 in 250, 1 in 1250 (P < 0.001) and at 1 in 6250 (P < 0.01).