Circulating antibodies to a conserved epitope of the Chlamydia trachomatis 60 kDa heat shock protein (hsp60) in infertile couples and its relationship to antibodies to C.trachomatis surface antigens and the Escherichia coli and human HSP60.

To evaluate the relationship between immunity to specific regions of the Chlamydia trachomatis 60 kDa heat shock protein (hsp60), autoimmunity to human HSP60 and infertility, sera from 50 women and 45 men seen for an infertility evaluation were tested. Humoral immunity to human HSP60 was detected in 18% of women and 8.9% of men while antibodies to the Escherichia coli hsp60 were detected in 12% of women and 4.4% of men. These differences were not statistically significant. In contrast, antibodies to a synthetic peptide epitope of the chlamydial hsp60, encompassing amino acids 260-271 (chsp 260-271), were present in sera from 16 (32%) of the women but in only six (13.3%) of the men (P=0.03). Antibodies to chsp 260-271 were present in 11 out of 17 (64.7%) individuals with high titre (>1:160) immunoglobulin (Ig)G antibody to C.trachomatis surface antigens as opposed to only two out of 15 (13.3%) with low titre antibody and two out of of 17 (11.8%) with undetectable chlamydial antibody (P < 0.004). Antibodies to chsp 260-271 were also associated with humoral immunity to human HSP60. 50% of sera with, as opposed to only 18.6% of sera without, anti-human HSP60 IgG were positive for antibodies to chsp 260-271 (P=0.03). In contrast, there was no relationship found between immunity to the E.coli hsp60 and antibodies to human HSP60. Antibodies to chsp 260-271 were more prevalent in women with at least two spontaneous abortions (eight out of 13, 61.5%) than in women with other infertility diagnoses (six out of 35, 17.1%) (P=0.004). Thus, immunity to chsp 260-271 is more prevalent in women than in men, associated with autoimmunity to human HSP60 and may be an immunological marker for spontaneous abortion.