Association of Mannose-binding Lectin Polymorphisms with Tuberculosis Susceptibility among Chinese

Tuberculosis (TB) is caused by infection of Mycobacterium tuberculosis. Host genetic variability is an important determinant of the risk of developing TB in humans. Although the association between MBL2 polymorphisms and TB has been studied in various populations, the results are controversial. In this study four functional single-nucleotide polymorphisms (SNPs, H/L, X/Y, P/Q and A/B) across the MBL2 gene were genotyped by direct DNA sequencing of PCR products in a case-control population of Chinese Han origin, consisting of 1,020 patients with pulmonary TB and 1,020 controls. We found that individuals carrying variant allele at A/B (namely BB or AB genotypes) was associated with increased susceptibility to TB (odds ratios [OR] = 1.57, 95% confidence interval [CI] 1.30-1.91, P = 1.3 × 10-6). Additionally, LYPB haplotype showed a significant association with increased risk of TB (OR = 1.54, 95% CI 1.27-1.87, P = 4.2 × 10-6; global haplotype association P = 3.5 × 10-5). Furthermore, individuals bearing low- or medium- MBL expression haplotype pairs had an increased risk of TB (OR = 1.56, 95% CI 1.29-1.90, P = 1.4 × 10-6). Thus, the reduced expression of functional MBL secondary to having MBL2 variants may partially mediate the increased susceptibility to TB risk.