GESTATIONAL-AGE CORRELATES WITH IMMUNOSUPPRESSIVE PROPERTIES OF HYDATIDIFORM MOLE PREGNANCIES

PROBLEM: Soluble trophoblast extracts (HME) from some human hydatidifo rm mole pregnancies suppress IL-2-dependent T-cell proliferation, whil e others express no immunosuppressive bioactivity. This study was desi gned to determine if suppression by HME was correlated with gestationa l age, uterine size, or hCG secretion. METHOD: Soluble extracts were p repared from nine hydatidiform mole trophoblast samples and screened f or immunosuppressive activity using a murine cytotoxic T-cell prolifer ation assay (CTLL-2). Gestational ages were determined from last menst rual cycle and uterine size was estimated at the time of surgery. Seru m samples were collected prior to uterine evacuation and were assayed for human chorionic gonadotropin (hCG). RESULTS: Four of nine HME samp les significantly (P < 0.05) suppressed CTLL2 proliferation, while fiv e exhibited no suppressive activity. A strong positive correlation (r = 0.639) was noted for the relationship between gestational age of the molar pregnancies and interleukin-2 (IL-2)-stimulated CTLL2 prolifera tion (expressed as % of control) in the presence of HME (500 mu g/mL). This indicates that HME suppression of CTLL2 proliferation is highest in early gestation and then declines with increasing gestational age. A similar correlation was observed between estimated uterine size at surgery and CTLL2 proliferation with added HME, although the associati on was not as strong (r = 0.359). No association was noted between hCG levels and CTLL2 proliferative responses (r = -0.091). CONCLUSIONS: T he results of this study suggest that production of immunosuppressive factors by hydatidiform mole trophoblast is developmentally regulated, and decreases with advancing gestation.