Seropositivity for the human heat shock protein (Hsp)60 accompanying seropositivity for Chlamydia trachomatis is less prevalent among tubal ectopic pregnancy cases than individuals with normal reproductive history

To investigate the role of anti-human heat shock protein 60 (hHsp60) antibody positivity in the pathogenesis of ectopic pregnancy, following Chlamydia trachomatis (CT) infection. In a case-control study, serological tests for anti-hHsp60 were performed in ectopic pregnancies (study group) and parturients with normal reproductive histories (control group). All participants in both groups were CT IgG(+). hHsp60 IgG(+) prevalences were compared between the two groups, by semiquantitative ELISA. Data were evaluated using nonparametric and parametric tests and multivariable regression. After an initial pilot study, two groups were formed: 63 ectopic gestations (study group) and 95 normal parturients (control group), all CT IgG(+). Blood samples from all cases were tested for anti-hHsp60 IgG. Age, gravidity, and practising contraception were higher in the control group, while a history of pelvic infections were more common in the study group. Hsp60 IgG(+) was found to be significantly higher in the control group (63/95, 66.3%) compared to study group (30/63, 47.6%). Regression analysis revealed anti-hHsp60 positivity was an independent factor delineating the two groups. Immunity to hHsp60 is less common in CT IgG(+) ectopic pregnancies than CT IgG(+) fertile subjects without a history of ectopic pregnancies. Hence, our findings suggest that hHsp60 seropositivity may decrease the probability of an ectopic gestation in subjects with previous CT infections.