Soluble HLA-DR levels in the maternal circulation of normal and pathologic pregnancy

Objective: The purpose of this study was to determine that circulating HLA-DR molecules are important candidates for the monitoring of maternal immunostimulation and immunosuppression. Study design: Concentrations of soluble HLA-DR molecules were estimated in EDTA plasma samples of 61 nonpregnant women, 123 healthy pregnant women in the second trimester, 66 healthy women who were delivered at term, and 136 women who were delivered because of complications such as uncontrollable preterm intrauterine activation, abruptio placentae, intrauterine growth retardation, preeclampsia, and HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome. Results: In comparison to nonpregnant women, the normal course of pregnancy was associated with strongly increasing levels of soluble HLA-DR from second trimester on until term. In comparison to women who were delivered preterm because of uncontrollable intrauterine activation, increased soluble HLA-DR concentrations were detected in case of HELLP syndrome (P < .05), although decreased levels were detected in the case of intrauterine growth retardation, preeclampsia (P < .01), and abruptio placentae (P < .01). Conclusion: Dysregulation of the maternal immune response to pregnancy may play an important role in the cause of complicated pregnancies. (Am J Obstet Gynecol 2003;188:473-9.)