Low levels of mannose-binding lectin confers protection against tuberculosis in Turkish children

Abstract

Mannose-binding lectin (MBL) plays an important role in innate immunity mediating phagocytosis and activating the MBL complement pathway. Few studies, conducted in adult populations, have shown that genetically determined low MBL levels may confer partial protection against tuberculosis (TB). In this study we aimed to investigate the relationships between the susceptibility to TB and two low producing MBL2 gene polymorphisms (codons 54 and 57) and MBL levels in children. Forty-four TB children (27 pulmonary TB, 17 extrapulmonary TB) and 99 age-matched healthy control children were included in the study. The mean age in the study group was 7.02 +/- 4.5 years. Genotyping of the MBL2 gene for codon 54 and 57 polymorphisms was carried out, and MBL levels in serum were also detected in all subjects from both groups. None of the subjects from either group showed codon 57 polymorphisms. The frequency of the AB genotype which produces low level MBL is significantly lower in the patients (9.1%) compared to control subjects (27.3%) (p < 0.011). The difference was especially significant between the extrapulmonary group and healthy controls (p < 0.006). The BB genotype was observed in only one child from the healthy controls and no children from the patient group. The median MBL plasma concentration was also significantly lower in the control group than that found in the study group (p = 0.036). These results indicate that low levels of MBL and AB genotype may be involved in the protection against tuberculosis, especially extrapulmonary tuberculosis in children.

The Deficiency of Serum Mannose Binding Lectin in Early Onset Idiopathic Pulmonary Fibrosis and Familial Cases

“…Our TB patients show an increased frequency of normal MBL levels, and this is considered a risk for infection due to competitive blocking of the MMR by MBL. While MBL deficiencies confer protection against TB infection [18,[30][31][32][33]. Sarcoidosis is associated with normal MBL levels similar to the healthy population including promoter and structural gene variants [28,29].…”

“…The TB group showed higher mean levels than HC, but this failed to reach significance (p=0.098) [18,30]. The literature on Tuberculosis show consistently that low MBL levels confer protection against TB, while higher levels are a risk for active disease [31][32][33]. There is no prior data in the literature for MBL levels in IPF.…”

No evidence of association between MBL2A/O polymorphisms and Mycobacterium tuberculosis infection in populations from the Brazilian Amazon region

“…This contrasts with the findings of Selvaraj et al [28], who suggested an association between the AA genotype and extra-pulmonary tuberculosis in patients infected with HIV-1. Cosar et al [22] also observed a significant reduction in the frequency of the AB genotype and the MBL2 ⁄ B allele in patients with extra-pulmonary tuberculosis, although there was no significant difference between the pulmonary patients and the healthy control group. Additionally, Singla et al [29] found the mutant allele MBL2 ⁄ B confers a protective role against TB in the study population.…”

“…To date, relatively few studies have investigated the impact of a deficiency of MBL on the susceptibility or resistance of individuals to tuberculosis [16,[20][21][22], and the available data are contradictory in relation to the role of this protein in this susceptibility. While Alagarasu et al [21] concluded that a deficiency of MBL was associated with an increase in susceptibility to tuberculosis, for example, other studies [22,23] indicated that it was associated with resistance to the disease.…”

“…While Alagarasu et al [21] concluded that a deficiency of MBL was associated with an increase in susceptibility to tuberculosis, for example, other studies [22,23] indicated that it was associated with resistance to the disease. The results of the present study were equally inconclusive, and no association was found between the variant genotypes (OO) that reduce the production of MBL [24] and either susceptibility or resistance to tuberculosis.…”