Seroreactivity to Chlamydia trachomatis Hsp10 correlates with severity of human genital tract disease

We have identified the chlamydial heat shock protein Hsp10 as a potential c orrelate to the immunopathogenic process in women with tubal factor inferti lity (TFI). The human serologic response to chlamydial Hsp10, Hsp60, and ma jor outer membrane protein (MOMP) was measured by enzyme-linked immunosorbe nt assay. Three populations of women were studied: uninfected controls (CU) , acutely infected (AI) women, and women with TFI. Sera from women in the A I and TFI groups both recognized Hsp10 more frequently and at a higher over all level than sera from healthy uninfected controls. Moreover, the inferti le women had significantly greater Hsp10 seroreactivity than acutely infect ed women, indicating a concomitant increase of Hsp10 recognition in populat ions with increasing levels of disease severity. Hsp60 reactivity showed a similar correlation in these populations, while MOMP reactivity peaked at t he same level in both AI and TFI populations but did not increase with dise ase severity. Test populations were standardized by level of reactivity to formalin-fixed Chlamydia trachomatis elementary bodies (EBs) to address whe ther these associations were reflections of increased overall chlamydial ex posure rather than a property specific to Hsp10. Associations between Hsp10 seropositivity and TFI were greater in the EB+ subgroup while associations among the EB- subgroup were diminished. When restricted to the EB+ subgrou ps, Hsp60 and MOMP responses in the TFI population did not increase signifi cantly over the level of AI group responses. Thus, among women with similar exposure to chlamydiae, the serologic response to Hsp10 exhibited a strong er correlation with TFI than did the response to Hsp60 or MOMP. These findi ngs support the hypothesis that the serological response to C. trachomatis heat shock proteins is associated with the severity of disease and identifi es Hsp10 as an antigen recognized by a significant proportion of women with TFI.