NEONATAL B CELL DIFFERENTIATION (RIFF)

Abstract

Perinatal factors influencing diff of cord blood B lymphocytes into immunoglobulin secreting plasma cells was studied in 126 neonates with gestational ages(GA) from 20-44 wks. A plaque forming cell assay measured background B cell diff and diff in response to pokeweed mitogen(PWM)plus hydrocortisone(HC). 8 infants had a GA less than 27.9 wks, 24 had GA's 28-32.9 wks, 30 had GA's 33-37.9 wks, 51 had GA's 38-41.9 wks and 13 had GA's above 42wks. The mean±SD GA was 36±5wks and B.Wt. 2400±980gm. The mean±SD background plaque formation was 98±253 and in response to PWM+HC was 7505±11874/106 cord blood mononuclear cells. B cell diff was observed in some neonates in all GA groups. The magnitude of in vitro neonatal B cell diff undergoes a continuous and significant(p<.002)reduction as GA increases. The influence of intrauterine nutritional deprivation(IUGR)on B lymphocyte diff was studied, and compared to GA matched controls with a normal intrauterine nutritional status. IUGR was not associated with a decrease in B cell responsiveness. Cesarean section and low one minute Apgar scores were associated with a significantly(p<.05)increased B lymphocyte diff. Although prolonged rupture of maternal amniotic membranes(PROM)was not singularly related to a significant increase in B cell diff, the combination of PROM and low Apgar scores(stress)was associated with a more significant increase(p<.003)than either factor alone. Thus, short term neonatal stress such as the combination of PROM and low Apgar scores has as much influence on neonatal B cell function as GA.