Soluble human leukocyte antigens, interleukin-6, and interferon-γ during pregnancy

PROBLEM: Soluble human leukocyte antigens (sHLA), interferon-γ (IFN-γ), and interleukin-6 (IL-6) were studied during human pregnancy to test the hypothesis that sHLA concentrations are regulated by these specific cytokines. METHOD OF STUDY: Enzyme-linked immunoadsorbent assays (ELISA) were used to measure sHLA I and II in maternal circulation, cord blood, and placenta effluents of pregnant and nonpregnant women; maternal serum cytokines were also determined. RESULTS: sHLA in maternal and cord blood were equivalent to that in the placenta. By the third trimester, sHLA I concentrations in maternal plasma were significantly reduced compared to the first or second trimesters. sHLA II was increased during the second trimester relative to that postpartum. Maternal IL-6 and IFN-γ concentrations were not statistically different throughout gestation or postpartum. CONCLUSIONS: These data do not suggest a role for maternal plasma IL-6 or IFN-γ in regulation of systemic sHLA class I during pregnancy, but they do not address whether such events take place in local tissues of the maternal-fetal unit.