203 Low Mannose Binding Lectin (MBL) Serum Levels And Hospital Acquired Infections (HAI) in Neonates in a Neonatal Intensive Care Unit (NICU)

Abstract

Background: MBL is a serum lectin, synthesised by the liver, that is part of the innate immune system; it behaves as an acute phase reactant and plays an auxiliary rather than a critical role in host defence. Individuals with MBL deficiency may experience an increased number of infections, particularly in the course of immunodeficiency (e.g. chemotherapy). A MBL concentration of 0.5 mcg/ml has been suggested as a cut-off level for MBL deficiency. Serum MBL levels in term neonates are similar to those in adults, but values in preterms are approximately 50% lower. HAI are an important cause of neonatal morbidity and mortality. Known risk factors account only in part of the (inter)individual variability of the frequency and severity of neonatal infections. Part of this variability could be related to individual differences in the maturation of the innate immune system. Aim: To investigate the relationship between MBL serum levels and incidence and severity of HAI in newborn infants admitted to a NICU. Methods: We studied retrospectively 190 neonates (133 preterm and 57 at term) consecutively admitted to a NICU. MBL serum levels were measured by a specific immunoassay (Antibody Shop, Copenhagen, Denmark) in all infants on admission; 68 infants subsequentely developed a HAI, defined according to the CDC definitions. Results: Median MBL serum levels on admission were 1.2 mcg/ml (IQR 0.2–2.9) in the whole sample, 0.9 mcg/ml (IQR 0.2 – 2.2) in preterm and 1.7 mcg/ml (IQR 0.3 – 3.9) in term infants (p<0.05). Median level on admission in infants who subsequently developed one or more HAI (0.5 mcg/ml; IQR 0.1 – 1.7), was significantly lower (p<0.001) than in those who did not develop HAI (1.5 mcg/ml; IQR 0.4 – 3.6;). Among infants with HAI, median MBL levels on admission were significantly lower in those who had two or more episodes of HAI than in those with only one episode (0.1 mcg/ml IQR 0.05– 0.5 vs 0.8 mcg/ml IQR 0.1–1.9; p<0.01), and in infants who developed HAI within 10 days following admission compared to those who developed HAI later on (0.2 mcg/ml IQR 0.05–1.2 vs 1.2.mcg/ml IQR 0.2–2.1; p<0.05). Among infants with HAI, MBL levels on admission were not significantly different in survivors and non survivors. Conclusion: Early MBL serum levels are low in neonates who subsequently develop HAI. Low MBL levels at birth are likely to represent a predisposing factor for infections in newborn infants.