Changes in plasma FcRIII demonstrate increasing receptor production during late pregnancy and after preterm birth

Pediatr Res. 1992 Nov;32(5):505-8. doi: 10.1203/00006450-199211000-00001.


We have previously described reduced expression of the Fc gamma receptor type III on the cell membrane (M-FcRIII) of neutrophils from very preterm neonates. To investigate the mechanism underlying this reduced receptor expression, we have measured neutrophil-derived soluble FcRIII (S-FcRIII) in the plasma of fetuses and neonates from 19 wk gestation. S-FcRIII in fetal plasma and in preterm neonates born before 32 wk gestation was consistently low [mean 13.6 +/- 1.2% (mean adult S-FcRIII = 100%, range 30-240%)]. In utero, S-FcRIII starts to rise from 33 wk and increases more than 4-fold to reach adult levels by term. S-FcRIII measured sequentially in preterm infants born as early as 24 wk of gestation showed a rapid postnatal increase to reach adult levels within 3 wk of birth. The changes in S-FcRIII paralleled changes in M-FcRIII expression on the cell surface. These observations point to a reduced rate of FcRIII production by fetal neutrophils as opposed to an increase in receptor release. The parallel increase in S-FcRIII and M-FcRIII suggests that there may be a programmed activation of FcRIII synthesis within individual cells late in the 3rd trimester of fetal development. In addition, FcRIII production may be switched on early by preterm birth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane / immunology
  • Female
  • Fetal Blood / immunology
  • Gestational Age
  • Humans
  • Infant, Newborn
  • Infant, Premature / immunology*
  • Neutrophils / immunology*
  • Pregnancy
  • Receptors, IgG / biosynthesis
  • Receptors, IgG / metabolism*
  • Solubility


  • Receptors, IgG