Asociación genética entre los Loci HLA-DRB1 y HLA-DQB1 con la susceptibilidad a padecer Lupus eritematoso sistemático / Genetic association between the Loci HLA-DRB1 and HLA-DQB1 with susceptibility to suffer from systemic lupus erythematosus

La investigación en Inmunogenética brinda información acerca de marcadores genéticos asociados con enfermedades autoinmunes, como el Lupus Eritematoso Sistémico (LES), se puede observar entonces ciertos factores de riesgo o protección hacia la enfermedad en una población determinada. OBJETIVO: Determinar la asociación genética entre los polimorfismos del Complejo Principal de Histocompatibilidad (CPH) representados por los loci HLA-DRB1 y HLA-DQB1 con la susceptibilidad a LES. METODOLOGÍA: Se trabajó con 85 pacientes lúpicos y 85 pacientes sin la enfermedad; se obtuvo DNA humano a partir de sangre periférica, se realizó un PCR-SSP de baja y alta resolución para tipificar molecularmente a los loci HLA-DRB1 y HLA-DQB1. Se determinó las frecuencias alélicas, las cuales fueron asociadas con ambas muestras mediante el uso del Odds Ratio, a un nivel de significancia del 5 %. RESULTADOS: Los resultados del PCR-SSP de baja resolución muestran que ningún alelo HLA tiene un rol predisponente, se observó que el alelo HLA-DRB1*04 presenta un rol protector OR=0,49 (p=0,03). Los resultados por PCR-SSP de alta resolución muestran que los alelos HLA-DRB1*03:01 (OR=18,3; p=0,007), DRB1*04:04 (OR=4,2; p=0,009), DRB1*09:01 (OR=18,3; p=0,007), HLA-QB1*03:03 (OR=18,8; p=0,006) y DQB1*02:01 (OR=21,2; p=0,003) son factores de riesgo. Se evidenció que los alelos HLA-DRB1*08:02 (OR=0,42; p=0,003) y HLA-DQB1*04:02 (OR=0,50; p=0,02) son de carácter protector. CONCLUSIONES: Los alelos que representan riesgo de padecer LES en la muestra estudiada son HLA-DRB1*03:01, 04:04, 09:01 y HLA-DQB1*03:03, 02:01. Los alelos que tiene un carácter protector a la enfermedad son HLA-DRB1*08:02 y HLA-DQB1*04:02.

Immunogenetics research provides information on genetic markers associated with autoimmune diseases such as systemic lupus erythematosus (SLE), you can then observe certain risk factors or protection to the disease in a given population. To determine the genetic association between polymorphisms of the Major istocompatibility Complex loci represented by the HLA-DRB1 and HLA-DQB1 with susceptibility to SLE. METHODOLOGY: We worked with 85 lupus patients and 85 patients without the disease; Human DNA was obtained from peripheral blood, PCR-SSP low and high resolution molecularly performed to establish the loci HLA-DRB1 and HLA-DQB1. Allele frequencies, which were associated with both samples using the Odds Ratio at a level of significance of 5% were determined. RESULTS: Results of PCR-SSP low-resolution HLA show that no predisposing allele plays a role, we observed that HLA-DRB1*04 allele has a protective role OR=0.49 (p=0.03). The PCR-SSP results of high resolution show that the HLA-DRB1*03:01 alleles (OR=18.3; p=0.007), DRB1*04:04 (OR=4.2; p=0.009), DRB1*09:01 (OR=18.3; p=0.007), HLA-QB1*03:03 (OR=18.8; p=0.006) and DQB1*02:01 (OR=21.2; p=0.003) are risk factors. We demonstrated that HLA-DRB1*08:02 alleles (OR=0.42; p=0.003) and HLA-QB1*04:02 (OR=0.50; p=0.02) are of a protective nature. CONCLUSIONS: The alleles representing LES risk in the study sample are HLA-DRB1*03:01, *04:04, *09:01 and HLA-DQB1*03:03, *02:01. The alleles having a protective character to the disease are HLADRB1* 08:02 and HLA-DQB1*04:02.

Molecular analysis of human leukocyte antigen class I and class II allele frequencies and haplotype distribution in Pakistani population.

AIM: Distribution of HLA class I and II alleles and haplotype was studied in Pakistani population and compared with the data reported for Caucasoid, Africans, Orientals and Arab populations. MATERIALS AND METHODS: HLA class I and II polymorphisms in 1000 unrelated Pakistani individuals was studied using sequence-specific primers and polymerase chain reaction and assay. RESULTS: The most frequent class I alleles observed were A*02, B*35 and CW*07, with frequencies of 19.2, 13.7 and 20%, respectively. Fifteen distinct HLA-DRB1 alleles and eight HLA-DQB1 alleles were recognized. The most frequently observed DRB1 alleles which represented more than 60% of the subjects were DRB1 *03, *07, *11 and *15. The rare DRB1 alleles detected in this study were HLADRB1 *08 and *09, having frequencies of 0.9 and 1.7%, respectively. In addition, at DRB1-DQB1 loci there were 179 different haplotypes and 285 unique genotypes and the most common haplotype was DRB1*15-DQB1*06 which represented 17% of the total DRB1-DQB1 haplotypes. In our population, haplotype A*33-B*58-Cw*03 comprised 2.8% of the total class I haplotypes observed. This haplotype was seen only in the oriental populations and has not been reported in the African or European Caucasoid. CONCLUSION: Our study showed a close similarity of HLA class I and II alleles with that of European Caucasoid and Orientals. In Pakistani population, two rare loci and three haplotypes were identified, whereas haplotypes characteristic of Caucasians, Africans and Orientals were also found, suggesting an admixture of different races due to migration to and from this region.