Mannose-binding lectin and mannose-binding protein-associated serine protease 2 levels and infection in very-low-birth-weight infants.

OBJECTIVE: The aim of this study was to explore the role of the lectin pathway in neonatal sepsis through the study of MBL and MASP2 levels and their relationship with infection in a cohort of very-low-birth-weight infants (VLBWI). METHODS: MBL and MASP2 were measured in plasma samples of n = 89 VLBWI using ELISA and correlated with clinical parameters. MBL plasma levels were aligned with genotyping data of mbl2 exon 1 polymorphisms, rs1800450, rs1800451, and rs5030737. RESULTS: MBL levels were clearly determined by MBL genotype, i.e., AA individuals had tenfold higher MBL levels than AO individuals. MBL and MASP2 levels did not correlate with gestational age, apart from MASP2 levels on day 7. During the first 21 days of life, we noted a gradual increase in both MBL and MASP2 levels. On day 7 of life, MASP2 levels in infants developing late-onset sepsis measured before the onset of symptoms were found to be lower, as compared to non-LOS infants. CONCLUSIONS: In our cohort of VLBWI, MBL levels were genetically determined, but not associated with gestational age or sepsis in the first 21 days of life. Lower MASP2 levels on day 7 may indicate increased risk for late-onset infection.

The association of mannose-binding lectin 2 polymorphisms with outcome in very low birth weight infants.

OBJECTIVES: Studies on the influence of mannose-binding lectin (MBL) deficiency on infection susceptibility in preterm infants have yielded controversial results. We investigated the association of genotype-based MBL levels with outcome in very-low-birth weight infants (VLBWI). METHODS: We genotyped 3 genetic variants of MBL2 (rs1800450, rs1800451, rs5030737) in 6878 VLBWI. MBL plasma levels were categorized as normal (wild type, A/A), low (heterozygotes, A/O) or undetectable (homozygotes, O/O). Primary outcome was the effect of genotype-based MBL2 levels on blood-culture proven and clinical sepsis during primary stay in hospital. We also evaluated burden of infection within 24 months after discharge. RESULTS: We found no association between MBL levels and sepsis risk in the whole cohort. Infants without measurable MBL levels born between 32 0/7 to 36 6/7 weeks of gestation, however, had a higher rate of Gram-negative sepsis than infants with normal or reduced MBL levels. In a follow-up investigation at 24 months (n = 1070 infants), infants without measurable MBL levels suffered more frequently from stomatitis and urinary tract infection. CONCLUSIONS: In a large cohort of VLBWI MBL2 deficiency had no major impact on infection risk unless children were born between 32 0/7 and 36 6/7 weeks of gestation.