Reduced expression of C5a receptors on neutrophils from cord blood
- aDepartment of Clinical Biochemistry, Odense University Hospital, bDepartment of Medical Microbiology
- Dr M Nybo Department of Clinical Biochemistry Odense University Hospital DK-5000 Odense CDenmark.m.nybo{at}winsloew.ou.dk
- Accepted 28 August 1997
Abstract
AIM To describe further functional deficiencies of neonatal neutrophils by measuring the expression of C5a receptors.
METHODS C5a uptake was measured using flow cytometry with fluorescein isothiocynate labelled recombinant C5a. The response of neutrophils to stimulation with C5a and fMLP was tested by measuring migration and exocytosis of myeloperoxidase and lactoferrin.
RESULTS C5a mean fluorescence on neutrophils from neonates was significantly lower (22.4 (SD 3.5)) than in adult controls (31.5 (3.1)). Neutrophils from neonates migrated poorly towards both C5a and fMLP compared with those from adult controls. Exocytosis of myeloperoxidase, but not lactoferrin from neonatal neutrophils stimulated with C5a, was significantly lower than in adult controls. fMLP stimulation, on the other hand, resulted in significantly higher exocytosis in neonates.
CONCLUSION The lower expression of C5a receptors on neutrophils from neonates could be related to reduced C5a mediated exocytosis of myeloperoxidase.
