ONTOGENY OF THE RESPONSE OF HUMAN PERIPHERAL-BLOOD T-CELLS TO GLUCOCORTICOIDS

The inhibitory effect of steroids such as dexamethasone on the immune response of adults has been widely documented. Little is known, howeve r, about the effect of these agents on the developing immune system in newborns. The present study describes the ontogeny of the sensitivity of peripheral blood T cells to dexamethasone during the first year of life. Cord blood T cells of preterm or term infants appear to be extr emely sensitive to inhibition of the proliferative response. This high sensitivity of cells to dexamethasone can still be observed in the fi rst 2 weeks after birth. Subsequently, the sensitivity to dexamethason e inhibition of T-cell proliferation gradually decreases. At 1 year of age, the adult response pattern has been acquired. (C) 1996 Academic Press, Inc.