Neonatal dexamethasone treatment induces long-lasting changes in T-cell receptor V beta repertoire in rats

Glucocorticoids are frequently administered for the prevention of chronic l ung disease in infants with respiratory distress syndrome. However, neonata l treatment may have consequences for immune functioning in the long-term. Here we demonstrate that neonatal glucocorticoid treatment has long-lasting effects on mRNA expression of several V beta genes within the CD4 and CD8 T cell subset in rats. Changes in the peripheral T cell V beta repertoire m ay be a consequence of altered intrathymic selection events in which cortic osterone plays an important role. Indeed, here we show that neonatal glucoc orticoid treatment affects corticosterone production by thymic epithelial c ells during neonatal life. In conclusion, changes in T cell V beta repertoi re after neonatal glucocorticoid treatment may contribute to altered immune reactivity in later life. (C) 2001 Elsevier Science BV. All rights reserve d.