RESUMO
To perform an investigation regarding the distribution of the human leukocyte antigen (HLA)-B27 subtypes in the Zulian population with ankylosing spondylitis (AS), 48 unrelated Mestizos, HLA-B27 positive by serology, were studied using the polymerase chain reaction-specific sequence oligonucleotides probe (PCR-SSOP) and specific sequence primers (SSP) to analyze the polymorphism in exons 2 and 3 of the HLA-B27 gene. Only two of eight HLA-B27 subtypes studied (B*2701-B*2708) were found. The distribution of these alleles in the population of patients was: B*2705, 68.8%, and B*2702, 31.2%. B*2705 subtype showed significant association with patients being male. In the healthy controls, the most common subtype was B*2708. These results were compared with frequencies reported in other Mestizo and Spanish populations and showed significant differences, such as a high frequency of B*2702. Such results show that HLA*B2705 and HLA*B2702 are the subtypes most frequently associated with AS in our Mestizo population and suggest a possible protector role for HLA*B2708, which was found only in the healthy population.
Assuntos
Predisposição Genética para Doença , Antígeno HLA-B27/genética , Espondilite Anquilosante/genética , Adolescente , Adulto , Envelhecimento , Alelos , População Negra , Primers do DNA , Etnicidade/genética , Feminino , Frequência do Gene , Genótipo , Antígeno HLA-B27/análise , Antígeno HLA-B27/classificação , Antígenos de Histocompatibilidade Classe I , Humanos , Indígenas Sul-Americanos/genética , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo Genético , Caracteres Sexuais , Espondilite Anquilosante/epidemiologia , Uveíte Anterior/epidemiologia , Uveíte Anterior/genética , Venezuela/epidemiologia , População BrancaRESUMO
OBJECTIVE: We investigated the distribution of HLA-B27 subtypes in patients with ankylosing spondylitis (AS) belonging to two ethnic groups of Colombia. MATERIAL AND METHODS: PCR-SSOs was used to detect the polymorphism in exons 2 and 3 of HLA-B27 in two groups of patients: 39 Mulattos and 20 Mestizos. Fifty-nine of them suffered of ankylosing spondylitis (AS), including two patients with ankylosing spondylitis plus anterior uveitis (AU). Only two out of eight HLA-B27 subtypes studied (B*2701-B*2708) were found. RESULTS: The distribution of these alleles in the whole population was: B*2705: 87.1% and B*2702: 12.8% in the Mulattos group; 80% were B*2705 and 20% B*2702 in Mestizos group. The distribution of HLA-B27 subtypes was: 84.74% of patients with AS were B*2705 and 15.26% B*2702. CONCLUSIONS: There was no significant difference in the distribution of HLA-B27 subtypes among the patients ethnic groups studied. Other authors have shown that B*2705, B*2702 and B*2704, the more frequent subtypes, are equally associated to the disease. Although population studies need to be done to analyze the distribution of subtypes between patients and controls, the low frequency of HLA-B27 within the normal population does not permit to do a representative number of controls; our results suggest that HLA-B*2705 and HLA-B*2702 are the subtypes more frequently associated with AS in patients from the two more prevalent patients ethnic groups in Colombia.