INTRODUÇÃO: O presente estudo foi desenhado para investigar um possível papel para os alelos HLA (histocompatibility leucocyte antigen) de classe I (HLA-A, -B, and -C) em pacientes com hanseníase do sul do Brasil. MÉTODOS: Duzentos e vinte e cinco pacientes com hanseníase e 450 indivíduos para o grupo-controle foram envolvidos nesse estudo. O genótipo HLA foi determinado por protocolos PCR-SSO (One Lambda, USA) e, a frequência desses alelos foi calculada em cada grupo por contagem direta e, após, comparadas. RESULTADOS: Houve associação entre HLA-A*11 (6,9% vs 4,1%; p = 0,0345; OR = 1,72; CI = 1,05 - 2,81), HLA-B*38 (2,7% vs 1,1; p = 0,0402; OR = 2,44; CI 95% = 1,05-5,69), HLA-C*12 (9,4% vs 5,4%; p = 0,01; OR = 1,82; CI 95% = 1,17-2,82) e HLA-C*16 (3,1 vs 6,5%; p = 0,0124; OR = 0,47; CI 95% = 0,26-0,85) e hanseníase per se. Além disso, as frequências de HLA-B*35, HLA-C*04 e HLA-C*07 foram diferentes entre os pacientes com as formas lepromatosa (LL) e tuberculoide (TT). Contudo, após o ajuste para o número de alelos comparados, os valores de p se tornaram não significativos. CONCLUSÕES: Embora nossos resultados não sustentem as conclusões anteriores de que os alelos HLA de classe I desempenham um papel na associação com a patogênese da hanseníase, sugerimos novos estudos devido à importância da associação entre HLA e KIR na resposta imune inata à hanseníase.

INTRODUCTION: The present study was designed to investigate a possible role of HLA (histocompatibility leucocyte antigen) class-I alleles (HLA-A, -B, and -C) in leprosy patients from Southern Brazil. METHODS: Two hundred and twenty-five patients with leprosy and 450 individuals for the control group were involved in this research. HLA genotyping was performed through PCR-SSO protocols (One Lambda, USA); the frequency of these alleles was calculated in each group by direct counting, and the frequencies were then compared. RESULTS: There was an association between HLA-A*11 (6.9% vs 4.1%, p=0.0345, OR=1.72, 95% CI=1.05-2.81), HLA-B*38 (2.7% vs. 1.1%, p=0.0402, OR=2.44, 95% CI=1.05-5.69), HLA-C*12 (9.4% vs. 5.4%, p=0.01, OR=1.82, 95% CI=1.17-2.82), and HLA-C*16 (3.1% vs. 6.5%, p=0.0124, OR=0.47, 95% CI=0.26-0.85) and leprosy per se. In addition, HLA-B*35, HLA-C*04, and HLA-C*07 frequencies were different between lepromatous (LL) and tuberculoid (TT) patients. However, after adjusting for the number of alleles compared, Pc values became nonsignificant. CONCLUSIONS: Although our results do not support the previous findings that HLA class-I alleles play a role in leprosy pathogenesis, we suggest new studies because of the importance of the association between the HLA and KIR in the innate immune response to leprosy.

O objetivo deste estudo foi padronizar uma metodologia de extração de DNA de alta qualidade a partir de amostras de sangue coagulado. Quarenta e oito amostras de sangue humano coagulado foram utilizadas para a extração de DNA pelo kit comercial EZ-DNA® (Biological Industries, Beit Haemek, Israel), pelo kit de coluna Neoscience® (One Lambda Inc., San Diego, CA) e pelo método modificado de salting out. Apenas o método de salting out foi capaz de extrair altas concentrações de DNA (média, 180ng/µL), as quais foram medidas pelo detector de fluorescência Qubit® (Invitrogen, USA). Este método permitiu a amplificação dos genes HLA (human leukocyte antigens) pela tecnologia PCR-SSO (polymerase chain reaction - specific sequence of oligonucleotides) Luminex, a qual exige DNA de boa qualidade, e de genes KIR (killer cell immunoglobulin-like receptors) pela técnica made in house PCR-SSP (polymerase chain reaction-sequence specific of primers), a qual demanda uma concentração específica de DNA (10ng/µL). Concluímos que a técnica de salting out modificada foi muito eficiente, simples e rápida para a extração de DNA de amostras de sangue humano coagulado, com o objetivo de realizar a genotipagem de genes HLA e KIR.

The objective of this study was to standardize a method for extracting high-quality DNA from samples of coagulated blood. Forty-eight samples of human coagulated blood were used for DNA extraction by means of the EZ-DNA® commercial kit (Biological Industries, Beit Haemek, Israel), the Neoscience® column kit (One Lambda Inc., San Diego, CA, USA) and a modified salting-out method. Only the salting-out method was able to extract high concentrations of DNA (mean, 180 ng/¼l), which were measured using the Qubit® fluorescence detector (Invitrogen, USA). This method enabled amplification of HLA (human leukocyte antigen) genes using the Luminex PCR-SSO (polymerase chain reaction - sequence-specific oligonucleotide) technology, which demands good quality DNA, and amplification of KIR (killer-cell immunoglobulin-like receptor) genes using an in-house PCR-SSP (polymerase chain reaction - sequence-specific primer) technique, which demands a specific concentration of DNA (10 ng/¼l). We concluded that the modified salting-out technique was very efficient, simple and fast for DNA extraction from human coagulated blood samples, with the aim of genotyping the HLA and KIR genes.