Abstract
Background. In fetal life the rates of proliferation and apoptosis are high. We studied if the rate of apoptosis decreases after birth, by measuring the soluble ( s) forms of Fas-Fas ligand and Tumor necrosis factor receptor 1 ( TNFR1)- TNF-α which attenuate apoptosis. Subjects and methods. Blood was drawn from the umbilical cord and from a peripheral vein on day 1 and 4 of life in 35 infants and sFas, sFas ligand, sTNFR1 and sTNF-α were determined by enzyme immunoassays. Data were analyzed by paired t -test and Pearson's correlation analysis. Results. sFas and sTNF increased significantly from birth to day 4 of life ( p =0.033 and p <0.0001 respectively), while sTNFR1 increased significantly from birth to day 1 of life ( p <0.0001) followed by a significant decrease on day 4 of life ( p <0.0001). The levels of sFas and sTNF-α on day 1 correlated with those on day 4 ( r =0.677, p <0.0002 and r =0.525, p <0.007 respectively). sFAS ligand was not detectable in any specimen. Conclusion. The increasing concentrations of the soluble molecules, sFas, sTNF-α and sTNFR1 might indicate that apoptosis may be downregulated in early postnatal life.