Complement and contact activation in term neonates after fetal acidosis.
OBJECTIVE
To evaluate complement and contact activation after fetal acidosis.


METHODS
Fifteen term neonates with hypoxic-ischaemic encephalopathy after umbilical arterial pH < 7.10 were compared with 15 healthy neonates with umbilical arterial pH > 7.20. Determinations of the complement function and C1-inhibitor activity were performed as kinetic tests 22-28 hours after birth. C1q, C1-inhibitor, and factor B concentrations were determined by radial immunodiffusion and those of C3a, C5a, and factor XIIa by enzyme immunoabsorbent assay.


RESULTS
Median complement function (46 vs 73%), C1q (4.3 vs 9.1 mg/dl), and factor B (5.2 vs 7.7 mg/dl) decreased after fetal acidosis. The activated split products C3a (260 vs 185 micrograms/l), C5a (5.0 vs 0.6 micrograms/l), and factor XIIa (3.2 vs 1.3 micrograms/l) increased in the neonates after fetal acidosis. No differences were found in the concentration and activity of C1-inhibitor.


CONCLUSIONS
Complement and contact activation occurred in the newborns with hypoxic-ischaemic encephalopathy. Activation of these systems generates mediators which can trigger inflammation and tissue injury.
Sonntag
J
J
Department of Neonatology Virchow-Klinikum, Humboldt-University, Berlin, Germany.
Wagner
M H
MH
Strauss
E
E
Obladen
M
M
D000138:Acidosis / Q000209:etiology / Q000276:immunology; D002545:Brain Ischemia / Q000209:etiology / Q000276:immunology*; D003167:Complement Activation; D003174:Complement C1 Inactivator Proteins / Q000032:analysis; D015922:Complement C1q / Q000032:analysis; D015926:Complement C3a / Q000032:analysis; D015936:Complement C5a / Q000032:analysis; D011415:Complement Factor B / Q000032:analysis; D015956:Factor XIIa / Q000032:analysis; D005260:Female; D005311:Fetal Hypoxia / Q000150:complications / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy
D003174:Complement C1 Inactivator Proteins; D015922:Complement C1q; D015926:Complement C3a; D015936:Complement C5a; D015956:Factor XIIa; D011415:Complement Factor B