HLA-B51 and its main subtypes in Brazilian patients with Behçet's disease

This study aimed to evaluate the frequency of HLA-B*51 and its subtypes in Brazilian patients with Behçet's disease (BD) and healthy controls (HC) and to assess possible associations with disease manifestations. A cross-sectional study with sequential BD patients and HC. HLAB*51 presence was determined by sequence-specific polymerase chain reaction (SSP-PCR) and HLA-B*51 subtypes by the Sanger sequencing method. Eighty-three BD patients and 258 HC were evaluated. HLA-B*51 was found in 30.1% of DB patients and in 15.5% of HC (p=0.003). The most prevalent subtypes in DB patients were HLA-B*51:01 (60.0%), HLA-B*51:08 (20.0%), HLA-B*51:22 (8.0%), HLAB* 51:29 (8.0%) and HLA-B*51:02 (4.0%), while HLA-B*51:01 (77.5%) and HLA-B*51:55 (7.5%) were the most prevalent in HC. HLA-B*51 was less frequently found in patients with neurologic involvement (8.0% vs. 29.3%; p=0.034) while HLAB*51:01 was more observed in patients with ocular involvement (93.3% vs. 60.3%; p=0.014). No BD patient with neurologic or vascular involvement presented HLA-B*51:01. HLAB*51:08 was more frequent in patients with vascular manifestations (60.0% vs. 15.4%; p=0.012). In multivariate analysis, 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 vascular manifestations of BD (OR = 14.843; 95%CI: 1.550 - 142.115; p=0.019). The prevalence of HLAB*51 is higher in Brazilian BD patients compared to HC, and it is a risk factor for BD. The HLA-B*51:08 subtype was independently associated with vascular manifestations of BD.