RESUMO
Tumor necrosis factor alpha (TNFalpha) plays a key role in orchestrating the complex events involved in inflammation and immune response. The presence of single nucleotide polymorphisms (SNPs) within the promoter region of the TNFa gene has been associated with a number of diseases. The aim of this study was to investigate the distribution of polymorphisms at positions -238 (G/A) and -308 (G/A) at the TNFalpha promoter, and its association to the outcome of different clinical forms of leprosy. Furthermore, the bacteriological index (BI) was evaluated among genotyped multibacillary (MB) patients in order to investigate the possible influence of each polymorphism on the bacterial load. This study included a total of 631 leprosy patients being 401 MB and 230 paucibacillary (PB), that was further separated according to its ethnicity (Afro- and Euro-Brazilians). The combination of SNPs in haplotypes generated three different arrangements: TNFG-G, TNFG-A and TNFA-G. In spite of the marked differences observed in the frequency of the haplotypes along the ethnic groups, no statistical differences were observed in haplotype frequencies between MB and PB patients. The BI analyses showed a lower bacteriological index among the -308 carriers, while the BI of the -238 carriers was higher. Although no significance has been achieved in this analysis regarding the influence of the polymorphisms to the development of the clinical outcome, it seems that in a different stage (among the MB patients) the polymorphisms could contribute to the degree of severity observed.
Assuntos
Hanseníase/genética , Mycobacterium leprae/crescimento & desenvolvimento , Polimorfismo de Nucleotídeo Único , Fator de Necrose Tumoral alfa/genética , População Negra , Brasil , DNA/química , DNA/genética , Feminino , Haplótipos , Humanos , Hanseníase/imunologia , Hanseníase/microbiologia , Masculino , Regiões Promotoras Genéticas , Análise de Regressão , Fator de Necrose Tumoral alfa/imunologia , População BrancaRESUMO
Dados recentes sugerem que o curso clinico dos estados reacionais na lepra esta estritamente relacionado a liberacao local ou sistemica de citocinas. Neste estudo, pacientes com ENL (erythema nodosum leprosum) foram agrupadas segundo a intensidade de seus sintomas clinicos. Os aspectos clinicos e imunologicos do ENL e os efeitos desses parametros na carga bacilar foram estabelecidos em conjuncao com a resposta imune in vitro desses pacientes, a antigenos microbacterianos. Em 10 de 17 pacientes testados, o indice bacteriano (IB) foi reduzido em pelo menos 1 log desde o diagnostico da lepra ate o aparecimento do primeiro episodio reacional, comparado a uma reducao esperada de 0.3 log no grupo reacional no mesmo periodo de MDT (multidrogaterapia)...