RESUMO
Leprosy is the major cause of non-traumatic neuropathy. Herein, we investigated the role of ninjurin 1, an adhesion molecule involved in nerve regeneration in leprosy. Our results demonstrated that M. leprae stimulates in vitro up-regulation of ninjurin mRNA in cultured Schwann and blood cells as well as in vivo mRNA and protein expression in leprosy nerve biopsies. A polymorphism (asp110ala) was investigated in a case-control study (1123 individuals) and no association was found with leprosy per se or with disseminated forms. Nevertheless, ala110 was associated with functional nerve impairment (OR=2.42; p=0.02 for ala/ala) and with lower mRNA levels. Our data suggests that asp110ala could be a valuable genetic marker of nerve damage in leprosy.
Assuntos
Moléculas de Adesão Celular Neuronais/genética , Hanseníase/complicações , Hanseníase/genética , Fatores de Crescimento Neural/genética , Nervos Periféricos/metabolismo , Doenças do Sistema Nervoso Periférico/genética , Polimorfismo de Nucleotídeo Único/genética , Adulto , Alanina/genética , Substituição de Aminoácidos/genética , Ácido Aspártico/genética , Moléculas de Adesão Celular Neuronais/química , Análise Mutacional de DNA , Feminino , Marcadores Genéticos/genética , Predisposição Genética para Doença/genética , Testes Genéticos , Genótipo , Humanos , Imunidade Inata/genética , Hanseníase/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fatores de Crescimento Neural/química , Nervos Periféricos/patologia , Nervos Periféricos/fisiopatologia , Doenças do Sistema Nervoso Periférico/diagnóstico , Doenças do Sistema Nervoso Periférico/fisiopatologia , RNA Mensageiro/metabolismo , Regulação para Cima/genéticaRESUMO
Studies carried out over the last decade have strongly suggested that TNF alpha both overtly participates in the cell-mediated immune response against Mycobacterium leprae, and is overproduced during reaction. In addition, reactions are intimately related to the onset of nerve damage. Finally, TNF alpha has been implicated in the pathogenesis of many human and experimental autoimmune peripheral neuropathies that, as in leprosy, result in demyelination and axonal lesions. Because of recent findings associating human TNF alpha mutant alleles at the -308 position with increased production of TNF alpha in many immunological and infectious diseases, an investigation of the role of TNF2 in predisposing leprosy patients to reaction has been undertaken. Analysis of 300 patients with leprosy--210 multibacillary and 90 paucibacillary--has shown that the percentage of reactional patients was similar among both carriers and non-carriers of the TNF2 allele. However, a separate analysis of 57 carriers of TNF2 found that reactions occurred much more frequently among heterozygous than among homozygous patients. Moreover, the frequency of neuritis was somewhat greater among the heterozygous patients than among the non-carriers. Enhanced serum levels of TNF alpha have been noted in both TNF-1 and TNF-2 mutant patients in the course of leprosy reaction. Our observations to date suggest that other factors not related to the presence of the mutant gene may lead to the TNF alpha hyper-responsiveness observed during reaction.