ASSOCIATIONS BETWEEN MATERNAL AND FETAL SERUM LEVELS OF IMMUNE ACTIVATION MARKERS AND FETAL GROWTH

During pregnancy, signs of maternal immunologic sensitization to fetal HLA and other fetoplacental alloantigens are often detectable in peri pheral blood. Presumably, this in part reflects immune activity at the maternal-fetal interface. This response may involve activation of mat ernal T cells, which stimulate placental growth via lymphokine product ion. To shed light on this mechanism, data on placental weight, neonat al anthropometry, gestational age, fetomaternal HLA relationships (ref lecting a potential for HLA allosensitization), and serum levels of th ree immune activation markers in maternal and cord blood were collecte d in a sample of 61 primiparous women and their neonates. The activati on markers were soluble CD8 antigen (sCD8), interleukin-2 receptor (sI L-2R), and beta-2 microglobulin (beta(2)m) Mean fetal and maternal sCD 8 and Pam levels, and mean fetal sIL-2R levels were significantly high er than published norms. Fetal means for all three markers exceeded ma ternal means, and both sIL-2R and beta(2)m were highly correlated betw een mother and fetus. This suggests that fetal sIL-2R and beta(2)m lev els result in part from transport or diffusion from the maternal compa rtment. No associations were found between fetomaternal HLA relationsh ips, activation markers, and placental weight. The difference between the fetal and maternal beta(2)m value was significantly correlated wit h birth weight, controlling for chest circumference and crown-heel len gth. Associations between birth weight and fetomaternal HLA relationsh ips could not be interpreted with certainty. These findings suggest th at maternal immune activation and diffusion or transport of Pam into t he fetal compartment enhances fetal growth in fat-free body mass. (C) 1995 Wiley-Liss, Inc.