Mannan-binding Lectin Concentrations Research Articles

Serum mannan-binding lectin (MBL) in patients with infection: clinical and laboratory correlates.

In this study, we determined the serum levels of mannan-binding lectin (MBL) in patients with suspected or documented infection to characterize the possible role of MBL in the susceptibility to infection. We also investigated the kinetics of MBL during the infection and correlated the concentrations of MBL with those of acute-phase reactants C-reactive protein (CRP) and group II phospholipase A2 (PLA2-II) and cytokines interleukin-1(IL-1). interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha). The frequency of MBL deficiency in the patients with signs of infection did not differ from that of controls. In four patients with MBL deficiency, the infections were caused by common pathogens and the outcome was normal. The mean MBL concentration in the patients with signs of infection was significantly higher than in the healthy controls (9.88 and 4.48 mg/l, respectively; p < 0.05). The highest mean MBL concentration was observed in patients with clinically or microbiologically documented bacterial infection. During follow-up, the MBL concentration altered individually in different patients, but no particular change in pattern in the MBL concentration could be demonstrated in any patient group. Of the acute-phase reactants in the circulation, only CRP and IL-1 showed a weak, albeit significant, negative correlation with the concentration of MBL. In conclusion, the deficiency of MBL was not shown to be an independent risk factor for infection in the adult population studied. The concentration of MBL did not follow the change in pattern of other acute-phase reactants and cytokines during the acute phase response. Therefore, measurement of the MBL concentration as an acute-phase reactant is not useful in the diagnosis or follow-up of infection. On the other hand, the deficiency of MBL can be detected reliably by serological methods even during an infection.

The plasma levels of conglutinin are heritable in cattle and low levels predispose to infection

Conglutinin, like mannan-binding lectin (MBL) and CL-43, is a serum collection involved in the innate immune defence system. In man, low serum MBL concentrations, resulting from mutations in the collagen region, are associated with a common opsonic defect. Plasma levels of conglutinin in cattle were assayed by rocket immunoelectrophoresis to examine whether they were genetically determined. Samples were collected from calves (309 bull-calves and 260 heifers with complex pedigree relationships). The number of respiratory infections from the 42nd to 336th day of life was recorded. The number of infections was found to be genetically determined (heritability: h2 = 0.31 +/- 0.07). A wide concentration range of conglutinin was found in plasma (< 1.25-35 micrograms/ml for females, geometric mean 8.1 micrograms/ml, and < 1.25-47 micrograms/ml for males, geometric mean 15.5 micrograms/ml), and the concentrations was found to be genetically determined (heritability, h2 = 0.52 +/- 0.07). The analysis revealed a negative association between disease frequency and the conglutinin levels (-0.56 +/- 0.18 for female; -0.50 +/- 0.18 for male). Levels of conglutinin below the detection limit of the assay (1.25 micrograms/ml) were found in 2% of the animals. If these animals are assumed to be homozygous for a single recessive allele causing low concentrations a gene frequency of 0.15 could be calculated. These findings suggests that selection for resistance against infectious disease is possible in cattle and that the level of plasma conglutinin may be a helpful trait in such a breeding scheme.