Humoral immune response to membrane components of Chlamydia trachomatis and expression of human 60 kDa heat shock protein in follicular fluid of in-vitro fertilization patients

Recent evidence suggests that Chlamydia trachomatis can persist in thefemale upper genital tract in an unculturable state. Since unsuspected C.trachomatis infection has been associated with adverse in-vitrofertilization (IVF) outcome we sought to detect further evidence of C.trachomatis in the genital tracts of women undergoing IVF. The prevalenceand distribution of antibodies to the major structural proteins of C.trachomatis in paired follicular fluid and sera of women undergoing IVFwere examined. Sera and follicular fluid samples from 149 women wereassayed for immunoglobulin (Ig)G and IgA antibodies to two C. trachomatisantigens, the major outer membrane protein (MOMP) and a recombinantlipopolysaccharide (rLPS) fragment. Additionally, the expression of human60 kDa heat shock protein (hsp 60) in follicular fluid was determined. Allcervical and follicular fluid samples were negative for C. trachomatis bypolymerase chain reaction, ligase chain reaction and DNA probe. Sera from60% of the subjects were positive for antichlamydial rLPS IgG; 36% werepositive for anti-MOMP IgG. Similarly, rLPS-directed and MOMP-directed IgAwere detected in sera of 34 and 14% of the subjects respectively. IgGantibodies to MOMP and rLPS were detected in 42 and 41% of the follicularfluid examined respectively. Anti-MOMP IgA was identified in 8.7% of thefollicular fluid while 27.5% were positive for anti-rLPS IgA. Human hsp 60expression was documented in 11.6% of the follicular fluid tested. IgAantibodies to both MOMP (P = 0.03) and rLPS (P = 0.02) in follicular fluidwere associated with a failure to become pregnant after embryo transfer.IgG antibodies in sera and follicular fluid and IgA antibodies in sera wereunrelated to IVF outcome. Similarly only anti- MOMP IgA (P = 0.02) andanti-rLPS IgA (P = 0.04) in follicular fluid were correlated with human hsp60 expression in follicular fluid. The unique association between IgAantibodies to two chlamydial antigens in follicular fluid and both hsp 60expression and IVF failure provides further support for the possibilitythat a persistent upper genital tract chlamydial infection contributes toIVF failure in some women.