Complement and contact activation related to surfactant response in respiratory distress syndrome.
The activation of inflammation and coagulation cascades is part of the pathogenesis of adult respiratory distress syndrome (RDS). Previous studies have demonstrated contact activation in preterm infants with RDS, whereas no concordant results have been found with complement activation. In this study, both systems were investigated in preterm infants with severe RDS and related to surfactant response. Thirty preterm newborns with severe respiratory distress (FiO2 > 0.5), but with no evidence of infection or fetal acidosis, were studied. Eighteen healthy preterm newborns of similar gestational age and birth weight served as controls. The study group was divided into two subgroups, according to their response to a porcine natural surfactant 6 h after administration: responders (FiO2 reduction > 50%) and poor responders (FiO2 reduction < or = 50%). C1q, C4, factor B, C3a, C5a, complement, and C1-inhibitor activity, as well as factor XIIa, were determined in blood samples, drawn 24 h after birth. Except for C1-inhibitor concentration and C1-inhibitor activity, all parameters for infants with severe RDS were different from controls. Complement precursor proteins were lower, and activated split products of the complement and contact system were higher. Infants with a poor response after application of surfactant showed higher amounts of C3a, C5a, and factor XIIa but lower C1q and C4 levels compared with infants with a good response to surfactant. Activation of the complement and the contact system was demonstrated in all respiratory distress patients. This activation was more pronounced in poor responders to exogenous surfactant.
Wagner
M H
MH
Department of Neonatology, Charité-Virchow-Hospital, Humboldt-University, Berlin, Germany.
Sonntag
J
J
Strauss
E
E
Obladen
M
M
D003167:Complement Activation; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012127:Respiratory Distress Syndrome, Newborn / Q000378:metabolism*; D012189:Retrospective Studies; D011503:Transglutaminases / Q000378:metabolism*
D011663:Pulmonary Surfactants; D011503:Transglutaminases