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Cell-surface expression of immunoglobulin G receptors on the polymorphonuclear leukocytes and monocytes of extremely
N R Payne1, J Frestedt, N Hunkeler
1Department of Neonatology, Minneapolis Children's Medical Center, Minnesota 55404.
Insights
Extremely premature infants show reduced expression of Fc gamma receptors (FcRIII and FcRII) on polymorphonuclear leukocytes (PMN) and monocytes. This decreased FcRIII expression on PMN is linked to birth weight and postnatal age.
Area of Science:
- Immunology
- Neonatology
- Cell Biology
Background:
- Fc gamma receptors (FcR) play a crucial role in immune responses.
- Understanding FcR expression in premature infants is vital for assessing immune function.
- Extremely premature infants have unique immunological profiles compared to term infants and adults.
Purpose of the Study:
- To quantify Fc gamma receptor (FcR) expression on polymorphonuclear leukocytes (PMN) and monocytes in extremely premature infants.
- To compare FcR expression levels between premature infants, term infants, and adults.
- To identify factors associated with altered FcR expression in premature neonates.
Main Methods:
- Flow cytometry was employed to measure FcRIII (CD16), FcRII (CD32), FcRI (CD64), CD14, and CD67 protein expression.
- The study included 64 extremely premature infants, 12 term infants, and 37 adults.
- Quantitative analysis of mean log channel fluorescence (MCF) and proportion of positive cells was performed.
Main Results:
- Premature infants exhibited significantly lower FcRIII and FcRII expression on PMN compared to term infants and adults.
- Monocytes from premature infants also showed reduced FcRIII and FcRII expression relative to adults.
- FcRIII expression on PMN was positively correlated with birth weight and postnatal age.
Conclusions:
- Extremely premature infants demonstrate diminished expression of FcRIII and FcRII on both PMN and monocytes.
- The reduced FcRIII expression on PMN in premature infants is associated with their birth weight and chronological age.
- These findings highlight potential immune system immaturities in extremely premature neonates.
Abstract:
This study measured Fc gamma receptor (FcR) expression on polymorphonuclear leukocytes (PMN) and monocytes from extremely premature infants. Flow cytometry was used to quantitate FcRIII [cluster of differention (CD) 16], FcRII (CD32), FcRI (CD64), CD14, and CD67 proteins on the PMN surface. Sixty-four premature infants with a mean gestational age +/- SD of 26 +/- 2 wk (birth weight = 847 +/- 217 g), 12 infants born at term (gestational age = 38 +/- 1 wk), and 37 adults were studied. Premature infants' PMN expressed less FcRIII, measured as mean log channel fluorescence (MCF), than did term infants or adults (MCF = 4.7 +/- 1.4, 6.1 +/- 1.0, and 8.8 +/- 1.8, respectively, p < 0.050). Premature infants also had a lower proportion of FcRIII-positive PMN than term infants or adults (mean +/- SEM = 0.83 +/- 0.02 versus 0.92 +/- 0.04 and 0.96 +/- 0.01, respectively, p < 0.050). FcRIII expression on PMN was positively associated with cell isolation procedures (p = 0.004), birth weight (p = 0.004), and postnatal age (p = 0.032). Premature infants also had lower PMN expression of FcRII when compared with adults and term infants (MCF = 2.4 +/- 0.6 versus 3.0 +/- 0.7 and 3.1 +/- 0.3, p < 0.050). Both premature and term infants had fewer FcRII positive PMN than did adults (mean +/- SEM = 0.90 +/- 0.09 and 0.89 +/- 0.07 versus 0.99 +/- 0.00, p < 0.050). Premature infants' monocytes also expressed significantly less FcRIII (MCF = 2.4 +/- 0.6 versus 3.4 +/- 0.9, p = 0.047) and FcRII (2.1 +/- 0.5 versus 2.9 +/- 0.6, p = 0.01) compared with adults. We conclude that extremely premature infants have decreased expression of FcRIII and FcRII on both their PMN and monocytes when compared with adults. The decrease in PMN FcRIII expression appears related to birth weight and chronologic age.