Functional haplotypes that produce normal ficolin-2 levels protect against clinical leprosy.

Host factors have been shown to play a significant role in the susceptibility to and clinical outcome of leprosy. Here, we analyze polymorphisms of the gene encoding ficolin-2 (FCN2), which is a soluble pattern-recognition molecule. A total of 158 patients with leprosy and 210 healthy control subjects from Brazil were investigated. Polymorphisms in the promoter and exon 8 of FCN2 were assessed by DNA sequencing. The distribution of functional FCN2 haplotypes amongpatients was significant different from that among the control subjects (P = .004). These results unveil an immunogenetic role for ficolin-2 in the host response against M. leprae.

The association between mannan-binding lectin gene polymorphism and clinical leprosy: new insight into an old paradigm.

BACKGROUND: Mannan-binding lectin (MBL), a soluble protein of innate immunity, is known to play a role in pathogen recognition and clearance. For more than a decade, it has been proposed that MBL deficiency may be protective against intracellular pathogens, such as Mycobacterium leprae. METHODS: The polymorphisms at the promoter and exon 1 regions of the MBL2 gene were assessed by polymerase chain reaction and sequencing performed on 264 patients with leprosy and 214 matched healthy control subjects from southern Brazil. RESULTS. The distribution of MBL2-gene polymorphisms in patients was significantly different from that in controls, with a decreased frequency of haplotypes/genotypes associated with low expression of circulating MBL in lepromatous patients when compared with tuberculoid patients (odds ratio [OR] for haplotypes, 0.56 [95% confidence interval {CI}, 0.33-0.93] [P=.020]; OR for genotypes, 0.31 [95% CI, 0.13-0.71] [P=.004]). The LYPA haplotype was associated with susceptibility to leprosy per se (OR, 2.25 [95% CI, 1.31-3.88] [P=.003]) and to progression to the lepromatous (OR, 2.2 [95% CI, 1.21-4.05] [P=.008]) and borderline (OR, 2.98 [95% CI, 1.29-6.87] [P=.008]) forms of the disease. CONCLUSIONS: These results suggest that MBL2-gene polymorphisms play a role in susceptibility to leprosy per se and in the clinical progression of the disease.