Abnormal FcRIII expression by neutrophils from very preterm neonates
R Carr and JM Davies
University Department of Haematology, Royal Liverpool Hospital, UK.
To further investigate the neutrophil dysfunction of newborn infants, we
have measured expression of the neutrophil Fc gamma receptors FcRIII and
FcRII in extremely immature preterm neonates born at 24 to 32 weeks of
gestation. Fc receptor expression was measured by FACS analysis of cells
stained with monoclonal antibody Leu11b for FcRIII and IV-3 for FcRII.
"Well" preterm neonates displayed reduced FcRIII, 51.05 +/- 2.0 (mean
fluorescence channel +/- SE) when compared with term neonates, 69.24 +/-
5.5 and adult controls, 71.83 +/- 3.0. "Stressed" preterm neonates with
severe respiratory distress syndrome or septicemia had a further
downregulation of FcRIII, 32.67 +/- 3.0 and 35.75 +/- 1.8, respectively,
associated with grossly abnormal cellular fluorescence distribution. In
well preterm neonates, expression of FcRIII improved to adult levels during
the first two postnatal weeks, suggesting a postnatal maturation of
function. Stressed neonates had signs of partial neutrophil activation
(increased Mac-1 expression and chemotactic ability), leading us to propose
that the further downregulation of FcRIII may be due to receptor shedding
in vivo by partially activated cells. FcRII expression was found to be
equivalent to adult levels in both well preterm and stressed neonates.
Reduced neutrophil FcRIII expression may provide some explanation for the
reported abnormalities of phagocytosis and bacterial killing in preterm
neonates.
Volume 76,
Issue 3,
pp. 607-611,
08/01/1990
Copyright © 1990 by The American Society of Hematology
