Mannan-binding lectin in neonates

Abstract number: 1733_1248

Szala A., MacDonald S., Domzalska-Popadiuk I., Atkinson A., Cedzynski M., Swierzko A., Szemraj J., Borkowska M., Szczapa J., Matsushita M., Turner M., Kilpatrick D.

Objectives: The mannan-binding lectin (MBL) protects the host from infection by lysis of microorganisms involving complement activation via the lectin pathway (LP). MBL may enhance phagocytosis by direct opsonisation. MBL deficiency may lead to the increased susceptibility to infection. It has been suggested to contribute to unexplained miscarriages and preterm births. We report some preliminary findings from ongoing prospective study of MBL levels, LP activities and mbl2 genotypes in Polish neonates.

Methods: MBL level in cord serum samples was determined in ELISA using specific monoclonal antibody (HYB 131–01, AntibodyShop). LP activity was determined as the ability to C4d deposition on mannan-coated plates. Genotyping was performed with the help of INNO-LIPA MBL2 kits (Innogenetics NV).

Results: The median MBL level in babies with suspected perinatal infections was 965 ng/mL (n = 203), and did not differ from that determined in newborns with no symptoms of infection (1093 ng/mL, n = 890). However, LP activity was significantly lower in the first group (181 mU/mL vs 267 mU/mL, p = 0.0017). The incidence of mbl2 gene defective alleles' (O/O) homozygosity (5.9%) was found to be almost twice that of the cohort in general (3.4%). The median MBL level in low birthweight (≤ 2500 g) babies (n = 86) did not differ from that of neonates with birthweights over 2500 g (n = 1006) (1048 vs 1076 ng/mL), however, LP activity was lower in low birthweight babies (161 vs 258 mU/mL, p = 0.006). Neither MBL nor LP differed between preterm and term babies, however the frequency of O/O genotypes among premature neonates was almost twice that of the cohort in general (6.2% and 3.2%, respectively).

Conclusion: The low LP activity may increase the risk of infection in perinatal period.

This study is partially supported by Ministry of Science and Higher Education (Poland), grant 2 P05E 011 28. Authors are very grateful to Innogenetics NV for providing INNO-LIPA MBL2 tests.