Polymorphisms in the TGFB1 and IL2RA genes are associated with clinical forms of leprosy in Brazilian population.

BACKGROUND Leprosy is a chronic infectious disease caused by Mycobacterium leprae, and compromises the skin and peripheral nerves. This disease has been classified as multibacillary (MB) or paucibacillary (PB) depending on the host immune response. Genetic epidemiology studies in leprosy have shown the influence of human genetic components on the disease outcomes. OBJECTIVES We conducted an association study for IL2RA and TGFB1 genes with clinical forms of leprosy based on two case-control samples. These genes encode important molecules for the immunosuppressive activity of Treg cells and present differential expressions according to the clinical forms of leprosy. Furthermore, IL2RA is a positional candidate gene because it is located near the 10p13 chromosome region, presenting a linkage peak for PB leprosy. METHODS A total of 885 leprosy cases were included in the study; 406 cases from Rondonópolis County (start population), a hyperendemic region for leprosy in Brazil, and 479 cases from São Paulo state (replication population), which has lower epidemiological indexes for the disease. We tested 11 polymorphisms in the IL2RA gene and the missense variant rs1800470 in the TGFB1 gene. FINDINGS The AA genotype of rs2386841 in IL2RA was associated with the PB form in the start population. The AA genotype of rs1800470 in TGFB1 was associated with the MB form in the start population, and this association was confirmed for the replication population. MAIN CONCLUSIONS We demonstrated, for the first time, an association data with the PB form for a gene located on chromosome 10. In addition, we reported the association of TGFB1 gene with the MB form. Our results place these genes as candidates for validation and replication studies in leprosy polarisation.

Polymorphisms in the TGFB1 and IL2RA genes are associated with clinical forms of leprosy in Brazilian population

BACKGROUND Leprosy is a chronic infectious disease caused by Mycobacterium leprae, and compromises the skin and peripheral nerves. This disease has been classified as multibacillary (MB) or paucibacillary (PB) depending on the host immune response. Genetic epidemiology studies in leprosy have shown the influence of human genetic components on the disease outcomes. OBJECTIVES We conducted an association study for IL2RA and TGFB1 genes with clinical forms of leprosy based on two case-control samples. These genes encode important molecules for the immunosuppressive activity of Treg cells and present differential expressions according to the clinical forms of leprosy. Furthermore, IL2RA is a positional candidate gene because it is located near the 10p13 chromosome region, presenting a linkage peak for PB leprosy. METHODS A total of 885 leprosy cases were included in the study; 406 cases from Rondonópolis County (start population), a hyperendemic region for leprosy in Brazil, and 479 cases from São Paulo state (replication population), which has lower epidemiological indexes for the disease. We tested 11 polymorphisms in the IL2RA gene and the missense variant rs1800470 in the TGFB1 gene. FINDINGS The AA genotype of rs2386841 in IL2RA was associated with the PB form in the start population. The AA genotype of rs1800470 in TGFB1 was associated with the MB form in the start population, and this association was confirmed for the replication population. MAIN CONCLUSIONS We demonstrated, for the first time, an association data with the PB form for a gene located on chromosome 10. In addition, we reported the association of TGFB1 gene with the MB form. Our results place these genes as candidates for validation and replication studies in leprosy polarisation.

The GATA3 gene is involved in leprosy susceptibitity in Brazilian patients

Leprosy outcome is a complex trait and the host-pathogen-environment interaction defines the emergence of the disease. Host genetic risk factors have been successfully associated to leprosy. The 10p13 chromosomal region was linked to leprosy in familial studies and GATA3 gene is a strong candidate to be part of this association. Here, we tested tag single nucleotide polymorphisms at GATA3 in two case-control samples from Brazil comprising a total of 1633 individuals using stepwise strategy. The A allele of rs10905284 marker was associated with leprosy resistance. Then, a functional analysis was conducted and showed that individuals carrying AA genotype express higher levels of GATA-3 protein in lymphocytes. So, we confirmed that the rs10905284 is a locus associated to leprosy and influences the levels of this transcription factor in the Brazilian population.

NOD2 and CCDC122-LACC1 genes are associated with leprosy susceptibility in Brazilians

Leprosy is a complex disease with phenotypes strongly influenced by genetic variation. A Chinese genome-wide association study (GWAS) depicted novel genes and pathways associated with leprosy susceptibility, only partially replicated by independent studies in different ethnicities. Here, we describe the results of a validation and replication study of the Chinese GWAS in Brazilians, using a stepwise strategy that involved two family-based and three independent case-control samples, resulting in 3,614 individuals enrolled. First, we genotyped a family-based sample for 36 tag single-nucleotide polymorphisms (SNPs) of five genes located in four different candidate loci: CCDC122-LACC1, NOD2, TNFSF15 and RIPK2. Association between leprosy and tag SNPs at NOD2 (rs8057431) and CCDC122-LACC1 (rs4942254) was then replicated in three additional, independent samples (combined OR(AA) = 0.49, P = 1.39e-06; OR(CC) = 0.72, P = 0.003, respectively). These results clearly implicate the NOD2 pathway in the regulation of leprosy susceptibility across diverse populations.

Toll-like receptor 1 N248S single-nucleotide polymorphism is associated with leprosy risk and regulates immune activation during mycobacterial infection.

Conflicting findings about the association between leprosy and TLR1 variants N248S and I602S have been reported. Here, we performed case-control and family based studies, followed by replication in 2 case-control populations from Brazil, involving 3162 individuals. Results indicated an association between TLR1 248S and leprosy in the case-control study (SS genotype odds ratio [OR], 1.81; P = .004) and the family based study (z = 2.02; P = .05). This association was consistently replicated in other populations (combined OR, 1.51; P < .001), corroborating the finding that 248S is a susceptibility factor for leprosy. Additionally, we demonstrated that peripheral blood mononuclear cells (PBMCs) carrying 248S produce a lower tumor necrosis factor/interleukin-10 ratio when stimulated with Mycobacterium leprae but not with lipopolysaccharide or PAM3cysK4. The same effect was observed after infection of PBMCs with the Moreau strain of bacillus Calmette-Guerin but not after infection with other strains. Finally, molecular dynamics simulations indicated that the Toll-like receptor 1 structure containing 248S amino acid is different from the structure containing 248N. Our results suggest that TLR1 248S is associated with an increased risk for leprosy, consistent with its hypoimmune regulatory function.

Toll-like receptor 1 N248S single-nucleotide polymorphism is associated with leprosy risk and regulates immune activation during mycobacterial infection

Conflicting findings about the association between leprosy and TLR1 variants N248S and I602S have been reported. Here, we performed case-control and family based studies, followed by replication in 2 case-control populations from Brazil, involving 3162 individuals. Results indicated an association between TLR1 248S and leprosy in the case-control study (SS genotype odds ratio [OR], 1.81; P = .004) and the family based study (z = 2.02; P = .05). This association was consistently replicated in other populations (combined OR, 1.51; P < .001), corroborating the finding that 248S is a susceptibility factor for leprosy. Additionally, we demonstrated that peripheral blood mononuclear cells (PBMCs) carrying 248S produce a lower tumor necrosis factor/interleukin-10 ratio when stimulated with Mycobacterium leprae but not with lipopolysaccharide or PAM3cysK4. The same effect was observed after infection of PBMCs with the Moreau strain of bacillus Calmette-Guerin but not after infection with other strains. Finally, molecular dynamics simulations indicated that the Toll-like receptor 1 structure containing 248S amino acid is different from the structure containing 248N. Our results suggest that TLR1 248S is associated with an increased risk for leprosy, consistent with its hypoimmune regulatory function.

NLRP1 haplotypes associated with leprosy in Brazilian patients

Polymorphisms in innate immunity genes are known to be involved in the multifactorial susceptibility to Mycobacterium leprae infection. M. leprae can downregulate IL-1ß secretion escaping monocyte digestion. The intracellular receptors NLRPs (NACHT, LRR and PYD domains-containing proteins) sense pathogen associated molecular patterns (PAMPs) activating caspase-1 and IL-1ß secretion in the context of inflammasome. Considering the possible role of inflammasome in the immune response against M. leprae, known single nucleotide polymorphisms (SNPs) in two NLRP genes, NLRP1 and NLRP3, were analyzed in Brazilian leprosy patients. Disease-associated SNPs (5 in NLRP1 and 2 in NLRP3), previously associated to infections and to immunologic disorders, were genotyped in 467 leprosy patients (327 multibacillary, MB; 96 paucibacillary, PB) and in 380 healthy controls (HC) from the state of Sao Paulo (Brazil), and in 183 patients (147MB; 64PB) and 186 HC from Mato Grosso (Brazil). Logistic regression analysis was performed considering susceptibility to leprosy di per se (leprosy versus HC) and clinical form (MB versus PB), adjusting for gender and ethnicity. Whereas none of the considered SNPs were statistically associated with leprosy, the NLRP1 combined haplotype rs2137722/G-rs12150220/T-rs2670660/G resulted significantly more frequent in patients than in HC as well as in PB than in MB. While both associations were lost after correction for gender and ethnicity, the NLRP1 combined haplotype rs2137722/G-rs12150220/A-rs2670660/G resulted strongly associated to PB. NLRP1 might be involved in the susceptibility to leprosy with particular emphasis for PB clinical form. Although preliminary, this is the first report linking NLRPs and inflammasome with leprosy: replication studies as well as functional assays are envisaged to deeper investigate the role of NLRP1 in M. leprae infection. Interestingly, NLRP1 SNPs were previously associated to susceptibility to Crohn disease, suggesting that NLRP1 could be a new modifier gene in common between leprosy and Crohn disease.

Epidemiologia genética em hanseníase: estudo de associação da região genômica candidata 6p21 e do gene TLR1 / Genetic epidemiology of leprosy: association study of the genomic region 6p21 canditate and TLR1 gene

A hanseníase é uma doença infecciosa crônica, que acomete pele e sistema nervoso periférico e tem como agente etiológico o Mycobacterium leprae, um patógeno exclusivamente intracelular, que tem predileção por macrófagos e pelas células de Schwann. É um traço complexo e fatores genéticos do hospedeiro têm sido repetidamente implicados com o risco para a doença. A região cromossômica 6p21 vem sendo sistematicamente envolvida com a hanseníase, não só pelos genes do HLA de classe II, como também pelos estudos envolvendo marcadores em genes como o TNF e a LTA. O gene TLR1 também é um importante candidato e polimorfismos deste já têm sido associados com hanseníase per se e com reação hansênica. O objetivo desta pesquisa foi conduzir estudo de associação de base populacional do tipo caso-controle em hanseníase testando marcadores do tipo tag SNPs em genes candidatos da região cromossômica candidata 6p21 e do gene TLR1. Oitenta e nove marcadores do tipo tag SNPs, localizados em trinta e seis genes foram genotipados. O presente trabalho envolveu 1718 indivíduos, 981 casos e 737 controles, provenientes de dois estados brasileiros: Mato Grosso e São Paulo. As genotipagens da população de Rondonópolis, MT foram realizadas em plataforma de médio rendimento (VeraCode GoldenGate Genotyping Assay – Illumina) e as genotipagens da população de São Paulo foram feitas usando discriminação alélica baseada na tecnologia TaqMan (Applied Biosystems). Para as análises estatísticas foi empregado modelo de regressão logística, com correção para as co-variáveis etnia e sexo, usando o software R, para Windows. Treze genes localizados na região 6p21 tiveram marcadores associados com hanseníase per se. O alelo S do polimorfismo N248S do gene TLR1 também foi associado com susceptibilidade para hanseníase per se...

Leprosy is an chronic infectious disease that attacks skin and peripheral nervous system. The causative agent is Mycobacterium leprae, an obligate intracellular pathogen that infects macrophage and Schwann cells. It is a complex trait and host genetic factors have been extensively implicated in leprosy susceptibility. The chromosomal region 6p21 has been involved with leprosy susceptibility due to HLA class II, and TNF and LTA genes, as well. The TLR1 gene is also an important candidate gene and polymorphisms at this locus have been associated to leprosy per se and leprosy reactions. This research is a population-based association study in leprosy which tested tag SNPs located at candidate genes in chromosomal region 6p21 and in TLR1 gene. Eighty-nine markers distributed in thirty-six genes were genotyped. The present work enrolled 1,718 individuals, 981 cases and 737 controls from Mato Grosso and São Paulo States, Brazil. The genotypes for Rondonópolis population were obtained using by medium-scale genotyping platform (VeraCode GoldenGate Genotyping Assay – Illumina), while to São Paulo samples the genotyping were done by allelic discrimination based on TaqMan technology (Applied Biosystems). Statistical analysis were performed by logistic regression models adjusted for the covariates sex and ethnicity, using R software. Thirteen genes located at 6p21 region presented markers associated to leprosy per se. The S allele for N248S polymorphism at TLR1gene was also associated to leprosy susceptibility...