Low-MBL producing genotypes playing a role on protection to leprosy and its multibacillary forms in a highly endemic area for leprosy in Brazil

The high frequency of MBL2 mutant alleles found in various human populations suggests that they provide some selective advantage. One of the hypotheses is that MBL deficiency may be protective against intracellular pathogens, including Mycobacterium leprae. In this study, we investigated the role of MBL2 in the susceptibility to leprosy. Single-nucleotide variants (SNV) B (rs1800450) and C (rs1800451) in exon 1 of the MBL2 gene and serum MBL concentrations were assessed in 53 patients with leprosy and 68 healthy controls from southeast Brazil by polymerase chain reaction followed by restriction fragment length polymorphism and commercial capture enzyme-linked immunosorbent assay, respectively. The genotyped SNVs were significantly associated with increased protection against leprosy (OR=0.3757, 95% CI=0.161508740, p=0.0273) and more severe forms, including multibacillary (OR=0.3769, 95% CI=0.14470.9818, p=0.0493) and lepromatous (OR=0.2423, 95% CI=0.065470.8968, p=0.0369) leprosy. On the other hand, low-MBL producing genotypes were associated with the protection for leprosy, especially in its more severe forms. Low MBL levels and low MBL producing variants were associated with protection against leprosy and progression to more severe forms of this disease. Moreover, this study highlights MBL as a regulator of immune function in which alterations may affect normal responses to leprosy infection and inflammatory stimuli.