Host defence lectins in preterm neonates

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.

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.

MBL serum concentrations were significantly lower in preterms <32 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 <28 wk GA suffering from RDS (4.4 ng/ml; 0.8-78.4 ng/ml; n=12).

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.