Background/Purpose: HLA-B*51 is considered the genetic marker mostly associated with Behçet’s disease (BD), mainly in countries of the silk route, where its prevalence ranges from 40-80% in individuals with BD. To date, the frequency of HLA-B*51 and its subtypes in Brazilian patients with BD and their associations with clinical manifestations of the disease are not known. The aims of this study are to evaluate the prevalence of HLA-B*51, B*51:01 and HLA-B*51:08 in Brazilian patients with BD and in healthy controls, to evaluate associations between HLA-B*51 and its subtypes and a higher risk for BD in the Brazilian population and to evaluate associations with specific clinical manifestations BD.

Methods: We carried out a cross-sectional study with BD patients and healthy controls. The presence of HLA-B*51 was investigated by sequence-specific polymerase chain reaction (PCR-SSP) and HLA-B*51 positive samples were submitted to genetic sequencing by the Sanger method to evaluate their alleles at medium resolution.

Results: Eighty-three BD patients and 258 healthy controls were evaluated. The prevalence of HLA-B*51 was 30.1% in DB patients and 15.5% in control subjects (p = 0.003). The most frequent alleles among DB patients were HLA-*51:01 (18.1%), HLA-B*51:08 (6.0%), HLA-B*51:22 (2.4%), HLA-B*51:29 (2.4%) and HLA-B*51:02 (2.1%), while HLA-B*51:01 (12.0%) and HLA-B*51:55 (1.2%) were the most frequent subtypes in the control group. Each of the other HLA-B*51 subtypes were observed in less than 1% of the control group. As for clinical manifestations, HLA-B*51 was less frequent in BD patients with neurological involvement (8.0% vs. 29.3%; p = 0.034) while HLA-B*51:01 was more frequently observed in BD patients with ocular involvement (93.3% vs. 60.3%; p = 0.014) and no BD patient with neurological involvement or vascular involvement had HLA-B*51:01. HLA-B*51:08 was more frequent in patients with vascular involvement (60.0% vs. 15.4%; p = 0.012). In the multivariate analysis, the presence of HLA-B*51 was an independent risk factor for BD (OR = 2.410; 95%CI: 1.332-4.361; p = 0.004) and HLA-B*51:08 had an independent association with the development of vascular manifestations of BD (OR = 14.843; 95%CI: 1.550 – 142.115; p = 0.019). No independent associations were observed between HLA-B*51 or with HLA-B*51:01 and disease manifestations of BD.

Conclusion: HLA-B*51 is more frequent in Brazilian BD patients compared to healthy controls and it is an independent risk factor for BD. The HLA-B*51:08 subtype was independently associated with vascular manifestations of BD.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/hla-b51-and-its-subtypes-in-brazilian-patients-with-behcets-disease/