Host defence lectins in preterm neonates

Aim: Deficiency in collectins is discussed as a risk factor for pulmonary and systemic infections in children and adults. The objective of this study was to determine serum concentrations of surfactant protein D (SP-D) and mannose-binding lectin (MBL) in preterm and term infants at birth. Methods: 47 preterm infants below 32 wk gestational age (GA) and 19 healthy, term newborn infants at birth have been included in the study, and SP-D as well as MBL concentrations have been determined in umbilical cord blood samples using sandwich ELISA technique. In addition, SP-D concentrations were assessed in tracheal aspirates ( TA) of 24 mechanically ventilated preterms and in infants without pulmonary complications before elective surgery. Results: MBL serum concentrations were significantly lower in preterms 532 wk GA (756.7 ng/ml; 14.6-11 184 ng/ml) compared to term newborns (3168.9 ng/ml; 282.3-7679.5 ng/ml; p = 0.005; median and range, respectively). Serum SP-D concentrations were significantly decreased in preterms between 28 and 32 wk GA (1.4 ng/ml; 0-4.6 ng/ml; n = 26) compared to term infants (2.2 ng/ml; 1.2-3.3 ng/ml; p = 0.05) and were found to positively correlate with history of antenatal corticosteroids and chorioamnionitis. SP-D concentrations in TA were increased in preterm infants between 28 and 32 wk GA with respiratory distress syndrome (RDS) (25.0 ng/ml; 0.9-44.7 ng/ml; n = 12) compared to control subjects (6.6 ng/ml; 0.5 - 30.4 ng/ml; n = 12) in contrast to extremely immature infants 528 wk GA suffering from RDS (4.4 ng/ml; 0.8 - 78.4 ng/ml; n = 12). Conclusion: In preterm infants, significant changes occur in collectin umbilical cord blood concentrations and pulmonary SP-D levels. Functional aspects of these findings need to be addressed further.