Avaliação de polimorfismos genéticos de L12RB2 e IFN-y em pacientes portadores de hanseníase

Abstract

Leprosy is an infectious disease characterized by different clinical forms that are associated with the type of immune response against Mycobacterium leprae. Polymorphisms present in the first intron of IFN- may have an important role in the regulation of the immune response, which could have functional consequences for gene transcription. Later studies identified the present of five polymorphisms in the IL12RB2 promoter region, this polymorphisms will may transcriptional factor suppress IL12R2 expression affect the development of cellular immune response. In the present study we investigated a possible association of the +874 T/A SNP and IFN-, microsatellite and polymorphisms present in the IL12RB2 promoter region associated with susceptibility to leprosy or with development of clinical forms in patients from brazilian Legal Amazon states. Nucleotide sequencing was performed with samples from 118 leprosy patients and 114 controls subjects, as well as immunophenotyping of CD4 +, CD8 + and CD69 + T cells by flow cytometry. Between leprosy patients and controls subjects, as well as between PB and MB patients were no observed significant differences among the studied genotypes in the polymorphisms of IL12RB2 studies. The polymorphisms -1035, -1023 and -464 present an absolute correlation (p<0.0001) having a combination of a same genotype in this positions. The microsatellite encoding 16 CA repeats was significantly associated with PB compared to MB patients (p = 0.019), being individuals homozygous for the +874 A allele present IFN- and the mean level of CD4 + and CD69 + T cells were higher. Our data suggest that polymorphisms present in the first intron of IFN- and of the IL12RB2 promoter region are not associated with susceptibility to leprosy, nevertheless, the +874 A/A genotype and microsatellite encoding 16 CA repeats may be related to a higher cellular immune response in patients and are consistently more frequently detected in PB patients.