Soluble HLA levels in early pregnancy after in vitro fertilization

Intact pregnancy can be interpreted as a state of maternal immunotolerance coward an haploidentical fetus. Soluble HLA (sHLA) molecules increase durin g episodes of allograft rejection and are discussed as candidates to modula te immune responses. We questioned whether after in vitro fertilization (IV F) the subsequent intact pregnancy, early abortion, or tubal pregnancy infl uence the courses sHLA serum levels. Therefore, serum samples of 65 IVF pat ients were assayed by ELISA for sHLA-I, sHLA-G, and sHLA-DR concentrations preovulatorily and after a positive HCG test weekly until the 9th gestation al week (GW). In 20 patients experiencing an early abortion the preovulator y sHLA-G mean level of 25.9 +/- 3.9 SEM ng/ml and the share of 4.2 +/- 0.8 SEM % on total sHLA-I were significantly (p < 0.05) reduced compared to wom en with intact pregnancy. The same differences (p < 0.0001) were seen durin g the monitoring of sHLA-G and sHLA-I levels in intact pregnancy versus ear ly abortion until 9th GW. Twin pregnancy revealed a drastically increase of sHLA-G levels from the 8th GW compared to singleton pregnancies. Further, individual sHLA-DR levels increased during intact pregnancy but decreased i n the group of early abortion. With regard to sensitivity and specificity f or pregnancy outcome sHLA quantitation reached similar weight as routine HC G determinations at GW 5. Especially women with preovulatory low sHLA-G lev els appear to be on risk for early abortion after IVF. (C) American Society for Histocompatibility and Immunogenetics, 2000. Published by Elsevier Sci ence Inc.