LYMPHOCYTE SUBSETS IN CORD-BLOOD OF PRETERM INFANTS - EFFECT OF ANTENATAL STEROIDS

The objective of this study was to evaluate prospectively the influenc e of gestational age (GA) and short-term antenatal steroids on total l ymphocyte count and lymphocyte subsets in cord blood from preterm infa nts. Two-color flow cytometric analyses of lymphocyte subsets were per formed on cord blood collected from 67 infants. These infants were gro uped according to GA: group I (term, n = 19); group II (GA 33-37 weeks , 25); group III (GA <33 weeks, n = 23). The mean absolute lymphocyte counts (ALC) in groups I, II and III were 5.6 +/- 2.5 x 10(3)/mu 1, 4. 3 +/- 1.5 x 10(3)/mu l and 3.5 +/- 1.8 x 10(3)/mu l respectively. The mean values for CD4+ lymphocytes in groups I, II and III were 2.7 +/- 0.8 x 10(3)/mu l, 2.0 +/- 0 0.8 x 10(3)/mu l and 1.6 +/- 0.9 x 10(3)/m u l respectively. Mean values for CD8+ lymphocytes were 0.9 +/- 0.3 x 10(3)/mu l, 0.6 +/- 0.3 x 10(3)/mu l and 0.5 +/- 0.3 x 10(3)/mu l resp ectively. With decreasing GA, there was a statistically significant de crease in ALC (p = 0.0035), CD4+ lymphocytes (p = 0.0013) and CD8+ lym phocytes (p = 0.0064). We then evaluated the effect of antenatal stero ids, now routinely administered to women with preterm onset of labor t o facilitate fetal lung maturation, and found that after adjusting for GA, infants of women on antenatal steroids had significantly fewer AL C (p = 0.0001), CD4+ lymphocytes (p = 0.02) and CD25+ lymphocytes (p = 0.03). In this population of infants, the decreased number of lymphoc ytes seen at younger GAs is associated with antenatal steroid use.