Putative pathogen-selected polymorphisms in the PKLR gene are associated with mycobacterial susceptibility in Brazilian and African populations.

Pyruvate kinase (PK), encoded by the PKLR gene, is a key player in glycolysis controlling the integrity of erythrocytes. Due to Plasmodium selection, mutations for PK deficiency, which leads to hemolytic anemia, are associated with resistance to malaria in sub-Saharan Africa and with susceptibility to intracellular pathogens in experimental models. In this case-control study, we enrolled 4,555 individuals and investigated whether PKLR single nucleotide polymorphisms (SNPs) putatively selected for malaria resistance are associated with susceptibility to leprosy across Brazil (Manaus-North; Salvador-Northeast; Rondonópolis-Midwest and Rio de Janeiro-Southeast) and with tuberculosis in Mozambique. Haplotype T/G/G (rs1052176/rs4971072/rs11264359) was associated with leprosy susceptibility in Rio de Janeiro (OR = 2.46, p = 0.00001) and Salvador (OR = 1.57, p = 0.04), and with tuberculosis in Mozambique (OR = 1.52, p = 0.07). This haplotype downregulates PKLR expression in nerve and skin, accordingly to GTEx, and might subtly modulate ferritin and haptoglobin levels in serum. Furthermore, we observed genetic signatures of positive selection in the HCN3 gene (xpEHH>2 -recent selection) in Europe but not in Africa, involving 6 SNPs which are PKLR/HCN3 eQTLs. However, this evidence was not corroborated by the other tests (FST, Tajima's D and iHS). Altogether, we provide evidence that a common PKLR locus in Africans contribute to mycobacterial susceptibility in African descent populations and also highlight, for first, PKLR as a susceptibility gene for leprosy and TB.

Epidemiological, temporal and spatial dynamics of leprosy in a municipality in northeastern Brazil (2008-2017): an ecological study.

INTRODUCTION: Leprosy is a chronic infectious disease caused by Mycobacterium leprae.This study aimed to analyze the epidemiological, temporal, and spatial dynamics ofleprosy in a municipality in northeastern Brazil. METHODS: This is an ecological study on new leprosy cases in the population of Arapiraca (Alagoas, Northeast Region, Brazil), from 2008 to 2017. Data extracted from a national database were analyzed forepidemiological indicators, factors associated with physical disabilities, and spatialanalysis in the neighborhoods of Arapiraca. RESULTS: A total of 292 new cases of leprosy were recorded, particularly occurring among the following groups: women, the age group of 46-59 years, brown-skinned individuals, people with less than eight years of schooling, and urban residents; the new cases were also predominantly the tuberculoid form and were of the paucibacillary classification of the disease. Almost 1/3 of the people had some degree of physical disability, which was mainly associated with the group 60 years of age and older, black ethnicity, and the multibacillary clinical form of leprosy. The joinpoint regression showed a stationary temporal behavior of indicators. There was a heterogeneous spatial distribution with active transmission areas, especially in the neighborhoods Primavera, Baixão, Ouro Preto, and downtown. CONCLUSIONS: The epidemiological indicators revealed complexity in the process of leprosy development. These spatial and temporal studies are relevant to help in the planning, monitoring, and guidance of interventions in the municipality. The spatial analysis showed heterogeneous distribution in the analyzed neighborhoods.

Epidemiological, temporal and spatial dynamics of leprosy in a municipality in northeastern Brazil (2008-2017): an ecological study

Abstract INTRODUCTION: Leprosy is a chronic infectious disease caused by Mycobacterium leprae.This study aimed to analyze the epidemiological, temporal, and spatial dynamics ofleprosy in a municipality in northeastern Brazil. METHODS: This is an ecological study on new leprosy cases in the population of Arapiraca (Alagoas, Northeast Region, Brazil), from 2008 to 2017. Data extracted from a national database were analyzed forepidemiological indicators, factors associated with physical disabilities, and spatialanalysis in the neighborhoods of Arapiraca. RESULTS: A total of 292 new cases of leprosy were recorded, particularly occurring among the following groups: women, the age group of 46-59 years, brown-skinned individuals, people with less than eight years of schooling, and urban residents; the new cases were also predominantly the tuberculoid form and were of the paucibacillary classification of the disease. Almost 1/3 of the people had some degree of physical disability, which was mainly associated with the group 60 years of age and older, black ethnicity, and the multibacillary clinical form of leprosy. The joinpoint regression showed a stationary temporal behavior of indicators. There was a heterogeneous spatial distribution with active transmission areas, especially in the neighborhoods Primavera, Baixão, Ouro Preto, and downtown. CONCLUSIONS: The epidemiological indicators revealed complexity in the process of leprosy development. These spatial and temporal studies are relevant to help in the planning, monitoring, and guidance of interventions in the municipality. The spatial analysis showed heterogeneous distribution in the analyzed neighborhoods.

Genetic polymorphisms of the IL6 and NOD2 genes are risk factors for inflammatory reactions in leprosy.

The pathways that trigger exacerbated immune reactions in leprosy could be determined by genetic variations. Here, in a prospective approach, both genetic and non-genetic variables influencing the amount of time before the development of reactional episodes were studied using Kaplan-Meier survival curves, and the genetic effect was estimated by the Cox proportional-hazards regression model. In a sample including 447 leprosy patients, we confirmed that gender (male), and high bacillary clinical forms are risk factors for leprosy reactions. From the 15 single nucleotide polymorphisms (SNPs) at the 8 candidate genes genotyped (TNF/LTA, IFNG, IL10, TLR1, NOD2, SOD2, and IL6) we observed statistically different survival curves for rs751271 at the NOD2 and rs2069845 at the IL6 genes (log-rank p-values = 0.002 and 0.023, respectively), suggesting an influence on the amount of time before developing leprosy reactions. Cox models showed associations between the SNPs rs751271 at NOD2 and rs2069845 at IL6 with leprosy reactions (HRGT = 0.45, p = 0.002; HRAG = 1.88, p = 0.0008, respectively). Finally, IL-6 and IFN-γ levels were confirmed as high, while IL-10 titers were low in the sera of reactional patients. Rs751271-GT genotype-bearing individuals correlated (p = 0.05) with lower levels of IL-6 in sera samples, corroborating the genetic results. Although the experimental size may be considered a limitation of the study, the findings confirm the association of classical variables such as sex and clinical forms with leprosy, demonstrating the consistency of the results. From the results, we conclude that SNPs at the NOD2 and IL6 genes are associated with leprosy reactions as an outcome. NOD2 also has a clear functional pro-inflammatory link that is coherent with the exacerbated responses observed in these patients.

Age-Dependent Association of TNFSF15/TNFSF8 Variants and Leprosy Type 1 Reaction.

A current major challenge in leprosy control is the prevention of permanent disabilities. Host pathological inflammatory responses termed type 1 reaction (T1R) are a leading cause of nerve damage for leprosy patients. The environmental or inherited factors that predispose leprosy cases to undergo T1R are not known. However, studies have shown an important contribution of host genetics for susceptibility to T1R. We have previously identified variants encompassing the TNFSF15/TNFSF8 genes as T1R risk factors in a Vietnamese sample and replicated this association in a Brazilian sample. However, we failed to validate in Brazilian patients the strong association of TNFSF15/TNFSF8 markers rs6478108 and rs7863183 with T1R that we had observed in Vietnamese patients. Here, we investigated if the lack of validation of these variants was due to age-dependent effects on association using four independent population samples, two from Brazil and two from Vietnam. In the combined analysis across the four samples, we observed a strong association of the TNFSF15/TNFSF8 variants rs6478108, rs7863183, and rs3181348 with T1R (pcombined = 1.5E-05, pcombined = 1.8E-05, and pcombined = 6.5E-06, respectively). However, the association of rs6478108 with T1R was more pronounced in leprosy cases under 30 years of age compared to the global sample [odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.54-2.46, pcombined = 2.5E-08 versus OR = 1.46, 95% CI = 1.23-1.73, pcombined = 1.5E-05]. A multivariable analysis indicated that the association of rs6478108 with T1R was independent of either rs7863183 or rs3181348. These three variants are known regulators of the TNFSF8 gene transcription level in multiple tissues. The age dependency of association of rs6478108 and T1R suggests that the genetic control of gene expression varies across the human life span.

A genome wide association study identifies a lncRna as risk factor for pathological inflammatory responses in leprosy.

Leprosy Type-1 Reactions (T1Rs) are pathological inflammatory responses that afflict a sub-group of leprosy patients and result in peripheral nerve damage. Here, we employed a family-based GWAS in 221 families with 229 T1R-affect offspring with stepwise replication to identify risk factors for T1R. We discovered, replicated and validated T1R-specific associations with SNPs located in chromosome region 10p21.2. Combined analysis across the three independent samples resulted in strong evidence of association of rs1875147 with T1R (p = 4.5x10-8; OR = 1.54, 95% CI = 1.32-1.80). The T1R-risk locus was restricted to a lncRNA-encoding genomic interval with rs1875147 being an eQTL for the lncRNA. Since a genetic overlap between leprosy and inflammatory bowel disease (IBD) has been detected, we evaluated if the shared genetic control could be traced to the T1R endophenotype. Employing the results of a recent IBD GWAS meta-analysis we found that 10.6% of IBD SNPs available in our dataset shared a common risk-allele with T1R (p = 2.4x10-4). This finding points to a substantial overlap in the genetic control of clinically diverse inflammatory disorders.

A genome wide association study identifies a IncRna as risk factor for pathological inflammatory responses in leprosy

Leprosy Type-1 Reactions (T1Rs) are pathological inflammatory responses that afflict a sub-group of leprosy patients and result in peripheral nerve damage. Here, we employed a family-based GWAS in 221 families with 229 T1R-affect offspring with stepwise replication to identify risk factors for T1R. We discovered, replicated and validated T1R-specific associations with SNPs located in chromosome region 10p21.2. Combined analysis across the three independent samples resulted in strong evidence of association of rs1875147 with T1R (p = 4.5x10-8; OR = 1.54, 95% CI = 1.32-1.80). The T1R-risk locus was restricted to a lncRNA-encoding genomic interval with rs1875147 being an eQTL for the lncRNA. Since a genetic overlap between leprosy and inflammatory bowel disease (IBD) has been detected, we evaluated if the shared genetic control could be traced to the T1R endophenotype. Employing the results of a recent IBD GWAS meta-analysis we found that 10.6% of IBD SNPs available in our dataset shared a common risk-allele with T1R (p = 2.4x10-4). This finding points to a substantial overlap in the genetic control of clinically diverse inflammatory disorders.

Association of IL10 Polymorphisms and Leprosy: A Meta-Analysis.

Leprosy is a chronic infectious disease that depends on the interplay of several factors. Single nucleotide polymorphisms (SNPs) in host immune related genes have been consistently suggested as participants in susceptibility towards disease. Interleukin-10 (IL-10) is a crucial immunomodulatory cytokine in mycobacterial pathogenesis and especially the -819C>T SNP (rs1800871) has been tested in several case-control studies indicating association with leprosy risk, although a recent consensus estimate is still missing. In this study, we evaluated the association of the -819C>T SNP and leprosy in two new Brazilian family-based populations. Then, we performed meta-analysis for this polymorphism summarizing published studies including these Brazilian family-based groups. Finally, we also retrieved published studies for other distal and proximal IL10 polymorphisms: -3575 T>A (rs1800890), -2849 G>A (rs6703630), -2763 C>A (rs6693899), -1082 G>A (rs1800896) and -592 C>A (rs1800872). Results from meta-analysis supported a significant susceptibility association for the -819T allele, with pooled Odds Ratio of 1.22 (CI = 1.11-1.34) and P-value = 3x10(-5) confirming previous data. This result remained unaltered after inclusion of the Brazilian family-based groups (OR = 1.2, CI = 1.10-1.31, P-value = 2x10(-5)). Also, meta-analysis confirmed association of -592 A allele and leprosy outcome (OR = 1.24, CI = 1.03-1.50, P-value = 0.02). In support of this, linkage disequilibrium analysis in 1000 genomes AFR, EUR, ASN and AMR populations pointed to r(2) = 1.0 between the -592C>A and -819C>T SNPs. We found no evidence of association for the other IL10 polymorphisms analyzed for leprosy outcome. Our results reinforce the role of the -819C>T as a tag SNP (rs1800871) and its association with leprosy susceptibility.

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.

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.

Leprosy susceptibility: genetic variations regulate innate and adaptive immunity, and disease outcome.

The past few years have been very productive concerning the identification of genes associated with leprosy. Candidate gene strategies using both case-control and family-based designs, as well as large-scale approaches such as linkage and gene-expression genomic scans and, more recently, genome-wide association studies, have refined and enriched the list of genes highlighting the most important innate and adaptive immune pathways associated with leprosy susceptibility or resistance. During the early events of host-pathogen interaction identified genes are involved in pattern recognition receptors, and mycobacterial uptake (TLRs, NOD2 and MRC1), which modulate autophagy. Another gene, LTA4H, which regulates the levels of lipoxin A4 and possibly interacts with lipid droplet-related events, also plays a role in the early immune responses to Mycobacterium leprae. Together, the activation of these pathways regulates cellular metabolism upon infection, activating cytokine production through NF-κB and vitamin D-vitamin D receptor pathways, while PARK2 and LRRK2 participate in the regulation of host-cell apoptosis. Concomitantly, genes triggered to form and maintain granulomas (TNF, LTA and IFNG) and genes involved in activating and differentiating T-helper cells (HLA, IL10, as well as the TNF/LTA axis and the IFNG/IL12 axis) bridge immunological regulation towards adaptive immunity. Subtle variations in these genes, mostly single nucleotide polymorphisms, alter the risk of developing the disease or the severity of leprosy. Knowing these genes and their role will ultimately lead to better strategies for leprosy prevention, treatment and early diagnosis. Finally, the same genes associated with leprosy were also associated with autoimmune (Crohn's disease, rheumathoid arthritis, psoriasis) or neurodegenerative diseases (Parkinson's and Alzheimer's). Thus, information retrieved using leprosy as a model could be valuable to understanding the pathogenesis of other complex diseases.