Analysis of the Frequency of the Toll-like 2 Gene Polymorphism in Leprosy

Polymorphisms in genes that are responsible for encoding cytokines and receptors involved in the immune response, such as Toll-like Receptor (TLR) 2 in leprosy, are of great interest for immunogenetic studies. This work aimed to analyze the possible association of single nucleotide polymorphism (SNP), synonymous, rs3804100 of the TLR2 gene with leprosy. The study was conducted in Bacteriology and Mycology section of Evandro Chagas Institute, Brazil between August 2020 and July 2021.The scope of the study consisted of 122 subjects from cities of Goianésia, Rondon, Curionópolis, Altamira, Parauapebas and Redenção of the State of Pará, Brazil. Genotyping was performed by conventional PCR and sequencing in the ABI 3130 Genetic Analyzer (Applied Biosystems®) using primer nucleotides designed by the Primer3Plus program from the genomic region “Homo sapiens toll like receptor 2 (TLR2) transcript variant X6, mRNA”, deposited in GenBank with reference XM_011532216.2. The analyzes were performed based on Fisher's exact test. It was managed in accordance with Helsinki Declaration and the Brazilian National Health Council and with approval of the ethics committee at Evandro Chagas Institute, under opinion number: 3.950.570. No associations between gender and leprosy were possible (P> 0.05). However, associations were observed between age groups, which were significant between those over 46 years old (P=0.004) and the 2nd dose of BCG as a more protective agent between the groups analyzed (P=0.004). For the subjects with the typed genotypes, 68 contacts had T/T genotype and only 4 T/C genotypes, while in multibacillary (MB) group only 1 T/C genotype was found and none in paucibacillary (PB) (P> 0.05). We conclude that there is no association between the TLR2 SNP rs3804100 and leprosy in the Pará population, which still indicates the need for new immunogenetic studies with other genes involved in the immune response and a greater number of polymorphisms.