257 COMPLEMENT ACTIVATION DURING FIRST HOURS OF LIFE IN PRETERM INFANTS WITH EARLY ONSET INFECTION

Abstract

Severe systemic infection is one of the most important causes for mortality and long term morbidity of preterm infants. Clear clinical signs often appear late, when the patients are actually decompensating. Laboratory tests for the detection of neonatal sepsis suffer from inter-observer differences (differential blood count) and time delay in significant increase (CRP = C-reactive protein). We previously have demonstrated the initial generation of anaphylatoxin C3a by alternative pathway activation of the complement system in severe early onset infection of term infants (Pediatries. 34:199-203,1993). In the present study we determined complement activation products of the alternative pathway, cytokine levels (IL-6) and CRP in preterm newborns with early onset systemic infection (n=19, gestational age 25-33weeks, median=29weeks). The control groups consisted of term (n=32) and preterm (n=20, gestational age 23-35 weeks, median=29weeks) newborns with no signs of infection within the first week of life. In the first six hours after birth infants with infection showed significantly higher C3a, C3bBbP (alternative convertase), TCC (terminal complement complex) and IL-6 levels compared with the control groups of term and preterm infants. After adequate treatment with antibiotics the parameters rapidly returned to slightly elevated or normal values within the first 48 hours of life. CRP, measured routinely as a marker of infection, showed a delayed increase which continued even after initiation of successful treatment. Thus CRP as an indicator of presumptive bacterial infection might be of little benefit in the initial course of an septic preterm infant, whereas complement activation products and IL-6 provide very early sensitive parameters of severe infection in both term and preterm infants.