RESUMO
ABSTRACT Background: The genetic predisposition to multiple sclerosis (MS) is associated with HLA alleles, especially HLA-DRB1*15:01. Objective: To identify associations between findings in magnetic resonance imaging (MRI) and genetic features in a Brazilian cohort of patients with MS. Methods: We retrospectively studied data from 95 consecutive patients with MS. Two independent observers who were blinded to the clinical data identified black holes and enhanced lesions on T1 MRI sequences, and counted and measured contrast-enhanced lesions on T2 and Flair (fluid attenuation inversion recovery) sequences. Cases were classified according to lesion size, number, and volume. The HLA-DRB1, HLA-DQB1, and HLA-DQA1 alleles, and the rs4774, rs3087456, rs6897932, rs731236, and rs1033182 single nucleotide polymorphisms were identified by polymerase chain reaction amplification with sequence-specific primers using the One Lambda Inc. Kit, Canoga Park, CA, USA. Results: Patients with the HLA-DQA1*04:01 allele had lesion load (adjusted for age, sex, and MS duration) above median compared with patients with other HLA-DQA1 alleles (p=0.02). There were no differences among all the other HLA alleles and single nucleotide polymorphisms and lesion load. Conclusions: The correlation of the HLA-DQA1*04:01 allele with a higher lesion load on T2/Flair MRI sequences suggests that the presence of this allele is associated with the risk of greater MS severity.
RESUMO Antecedentes: A predisposição genética para a esclerose múltipla (EM) está associada a alelos HLA, principalmente o HLA-DRB1*15:01. Objetivo: Identificar associações entre lesões na ressonância magnética e características genéticas em uma coorte brasileira de pacientes com EM. Métodos: Estudamos retrospectivamente os dados de 95 pacientes consecutivos com EM. Dois observadores independentes que desconheciam os dados clínicos identificaram "black holes" e lesões realçadas pelo contraste nas sequências de ressonância magnética T1 e contaram e mediram as lesões nas sequências T2 e FLAIR (fluid attenuated inversion recovery). Os casos foram classificados de acordo com tamanho, número e volume da lesão. Os alelos HLA-DRB1, HLA-DQB1 e HLA-DQA1 e os polimorfismos de nucleotídeo único rs4774, rs3087456, rs6897932, rs731236 e rs1033182 foram identificados por amplificação de reação em cadeia da polimerase com iniciadores específicos de sequência usando o kit One Lambda Inc., Canoga Park, CA, EUA. Resultados: Os pacientes com alelo HLA-DQA1*04:01 apresentaram carga de lesão (ajustada para idade, sexo e duração da EM) acima da mediana em comparação com outros pacientes com demais alelos HLA-DQA1 (p=0,02). Não houve diferenças entre todos os outros alelos HLA e polimorfismos de nucleotídeo único e carga lesional. Conclusões: A correlação do alelo HLA-DQA1*04:01 com maior carga de lesão nas sequências de RM em T2 sugere que a presença desse alelo pode estar associada ao risco de maior gravidade da EM.
Assuntos
Humanos , Cadeias alfa de HLA-DQ/genética , Esclerose Múltipla/genética , Esclerose Múltipla/diagnóstico por imagem , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Genes MHC da Classe II , Predisposição Genética para Doença , Alelos , Cadeias beta de HLA-DQ , Cadeias HLA-DRB1/genética , Frequência do GeneRESUMO
ABSTRACT Objective To evaluate the frequency of DQ2.5 and DQ8 alleles using the Tag-single-nucleotide polymorphism (Tag-SNP) technique in individuals with type 1 diabetes mellitus (T1DM) and celiac disease (CD) in southern Brazil. Materials and methods In a prospective design, we performed the search for DQA1*0501 and DQB1*0201 alleles for DQ2.5 and DQB1*0302 for DQ8 through Real-Time Polymerase Chain Reaction (RT-PCR) technique, using TaqMan Genotyping Assays (Applied Biosystems, USA). The diagnosis of CD was established by duodenal biopsy and genotypic determination performed by StepOne Software v2.3. Allelic and genotypic frequencies were compared between groups using Chi-square and Fisher's exact tests and the multiple comparisons using Finner's adjustment. Results Three hundred and sixty two patients with a median age of 14 years were divided into 3 groups: T1DM without CD (264); T1DM with CD (32) and CD without T1DM (66). In 97% of individuals with T1DM and CD and 76% of individuals with CD without T1DM, respectively, the alleles DQ2.5 and/or DQ8 were identified (p < 0.001). DQ2.5 was more common in individuals with CD (p = 0.004) and DQ8 was more common in individuals with type 1 diabetes (p = 0.008). Conclusions The evaluation of the alleles for DQ2.5 and DQ8 by Tag-SNP technique showed a high negative predictive value among those with T1DM, similar to that described by the conventional technique. The high frequency of DQ8 alleles in individuals with T1DM did not allow differentiating those at higher risk of developing T1DM.
Assuntos
Humanos , Masculino , Feminino , Doença Celíaca/genética , Predisposição Genética para Doença/genética , Diabetes Mellitus Tipo 1/genética , Frequência do Gene/genética , Doença Celíaca/complicações , Estudos Prospectivos , Fatores de Risco , Polimorfismo de Nucleotídeo Único , Diabetes Mellitus Tipo 1/complicações , Cadeias alfa de HLA-DQ/genética , Cadeias beta de HLA-DQ/genética , Reação em Cadeia da Polimerase em Tempo Real , GenótipoRESUMO
La variabilidad genética relacionada al sistema inmune del huésped ha sido propuesta como uno de los factores más influyentes en el desarrollo de enfermedades causadas por HPV. Caso clínico: Reportamos el caso de un niño de 5 años en cuyo estudio por disfonía crónica se encuentra papilomatosis laríngea probablemente adquirida por vía vertical durante el parto. El diagnóstico de papilomatosis laríngea se confirmó con una biopsia tras una primera cirugía orientada a remover los papilomas. Se utilizó el sistema de clasificación Derkay para evaluar la severidad de la papilomatosis. Se realizó genotipificación en biopsia demostrándose HPV-6. Posteriormente mediante tipificación de alelos HLA se demostró homocigosis para los alelos HLA-DQA1*0505, -DQB1*0301, -DRB1*1101. Conclusiones: Se necesitan estudios adicionales que permitan identificar los alelos HLA más prevalentes en población latina y su potencial asociación con la susceptibilidad genética en Papilomatosis Respiratoria Recurrente.
Genetic variability related to the host immune system has been proposed as one of the most influential factors in the development of diseases caused by HPV. Clinical case: We report the case of a 5-year-old child in whom chronic laryngeal papillomatosis, probably acquired vertically during labor, was detected. The diagnosis of laryngeal papillomatosis was confirmed with a biopsy after a first surgery to remove the papillomas. The Derkay classification system was used to assess the severity of papillomatosis. Biopsy genotyping was performed by demonstrating HPV-6. Later, HLA-DQA1 * 0505, -DQB1 * 0301, -DRB1 * 1101 alleles were homozygous for HLA allele typing. Conclusions: Further studies are needed to identify the most prevalent HLA alleles in the Latino population and their potential association with genetic susceptibility in Recurrent Respiratory Papillomatosis.