Pos1553 the significant association of hla-a26 with uveitis and gastrointestinal involvement in patients with behçet’s disease in a multicenter study

Background Specific haplotypes of human leukocyte antigen (HLA) are associated with susceptibility and disease activity of Behçet’s disease (BD). However, the clinical importance of HLA-A26 in BD is not well recognized compared to that of HLA-B51. Objectives This study aimed to examine the association between HLA-A26, HLA-B51, clinical manifestations, and disease severity in BD, especially focusing on HLA-A26 possession. Methods This study was a multicenter cross-sectional observational study and patients with BD were enrolled from 2006 to 2021. All patients met the International Criteria for BD [1] or the diagnostic criteria of the Behçet’s Disease Research Committee of Japan [2]. Disease severity was evaluated using Krause score reflecting the entire spectrum of disease manifestations [3]. Both serotypes and genotypes were accepted for HLA typing. Results In total, 200 patients were enrolled in this study. Uveitis was observed in 95/196 patients (48.5%) and gastrointestinal involvement in 57/167 patients (34.1%). HLA haplotypes were identified for HLA-B51 (n = 52/106, 49.1%), HLA-A26 (n = 25/88, 28.4%), and both HLA-B51 and HLA-A26 (n = 6/88, 6.8%). While HLA-A26 showed no significant association with clinical manifestations without adjustment for HLA-B51, HLA-A26 possession showed a higher frequency of uveitis (HLA-A26 positive vs. negative: n = 6/6, 100% vs. n = 16/32, 50.0%, respectively, p = 0.03) and higher Krause scores (median: 7 vs. 5, respectively, p = 0.02) under conditions with HLA-B51. Furthermore, the association between uveitis and gastrointestinal involvement was influenced by HLA-A26: HLA-A26 possession was associated with a higher frequency of uveitis in patients with gastrointestinal involvement (HLA-A26 positive vs. negative: n = 5/9, 55.6% vs. n = 0/21, 0%, respectively, p = 0.001), as well as for gastrointestinal involvement in patients with uveitis (HLA-A26 positive vs. negative: n = 5/11, 45.5% vs. n = 0/24, 0%, respectively, p = 0.001). All 5 patients with both uveitis and gastrointestinal involvement had HLA-A26 (HLA-A26 positive vs. negative: n = 5/21, 23.8% vs. n = 0/58, 0%, respectively, p = 0.001). Conclusion HLA-A26 was associated with severity of BD and uveitis in patients with HLA-B51, and was associated with coexistence of uveitis and gastrointestinal involvement. This study suggested the importance of confirming HLA-A haplotype in patients with BD. References [1]J Eur Acad Dermatol Venereol. 2014; 28(3): 338-47. [2]Y Mizushima, G Inaba, Y Mimura. Report of Behçet’s Disease Research Committee, Japan; 1987. 8-17. [3]I Krause, et al. J Rheumatol. 2001; 28(5): 1033-6. Table 1. Comparison of clinical characteristics of BD patients with and without HLA-A26 Total (n = 88) HLA-B51 (+) (n = 38) Uveitis (+) (n = 40) Gastrointestinal involvement (+) (n = 30) Uveitis†, % 56.0 vs. 41.3, p = 0.24 100 vs. 50.0, p = 0.03 - 55.6 vs. 0, p = 0.001 Gastrointestinal involvement†, % 42.9 vs. 36.2, p = 0.61 60.0 vs. 24.1, p = 0.14 45.5 vs. 0, p = 0.001 - Uveitis + Gastrointestinal involvement†, % 23.8 vs. 0, p = 0.001 60.0 vs. 0, p = 0.002 - - Krause score¶, mean 6 vs. 5, p = 0.43 7 vs. 5, p = 0.02 7 vs. 6, p = 0.27 6.5 vs. 5, p = 0.04 †: HLA-A26 positive (%) vs. negative (%); Fisher’s exact test ¶: HLA-A26 positive vs. negative; Mann-Whitney U test Figure 1. Association between haplotypes and clinical manifestations Acknowledgements: NIL. Disclosure of Interests None Declared.