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-alpha 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-alpha 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-alpha 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-alpha and sTNFR1 might indicate that apoptosis may be downregulated in early postnatal life.