Behçet’s disease in HLA-B*51 negative Germans and Turks shows association with HLA-Bw4-80I
1 Department of Internal Medicine II, Section for Transplantation Immunology and Immunohematology, University of Tübingen, Waldhoernle Str. 22, 72072 Tübingen, Germany
2 Interdisciplinary Centre for Rheumatology Stuttgart (ZIRS), Stuttgart, Germany
3 Centre for Interdisciplinary Clinical Immunology, Rheumatology and Auto-inflammatory Diseases-INDIRA and Department of Internal Medicine II, University of Tübingen, Tübingen, Germany
4 Scientific Research Institute of Traumatology and Orthopedics, Astana, Kazakhstan
5 National Center for Biotechnology, Astana, Kazakhstan
Arthritis Research & Therapy 2014, 16:R116 doi:10.1186/ar4569Published: 26 May 2014
Behçet’s disease (BD) as systemic vasculitis of unknown etiology is associated with HLA-B*51 in European and Asian populations. HLA-A*26 was claimed as an additional BD susceptibility marker in Japanese and Greek patients. This study was performed to test for HLA associations in HLA-B*51 negative German and Turkish BD populations.
In total, 65 German and 46 Turkish patients lacking HLA-B*51 were analyzed in comparison to healthy HLA-B*51 negative Germans (n = 1500) and Turks (n = 130). HLA-A/B genotypes were determined by SSOP. P-values with correction for multiple testing (pc), χ2-test and odds ratio (OR) were used for statistical evaluation.
HLA-A*26 was significantly more frequent in HLA-B*51− German patients [pc = 0.0076, OR = 3.23, 95% CI 1.63 to 6.39] than in respective controls. HLA-A*26 was also elevated in a smaller group of Turkish patients versus the controls. Significant association of HLA-Bw4 with isoleucine at amino-acid position 80 (HLA-Bw4-80I) was found in the HLA-B*51− German cohort of BD patients [pc = 0.0042, OR = 2.35, 95% CI 1.41 to 3.93) and in the Turkish patients in comparison to the respective controls [p = 0.025, OR = 2.17, 95% CI 1.09 to 4.31]. On the contrary, HLA-Bw4-80 T was reduced in both HLA-B*51− BD patient cohorts.
The study shows a significant association of HLA-Bw4-80I present on HLA-B*51 as well as on other B-locus molecules with BD. This indicates that distinctive Bw4 epitopes on HLA-B locus molecules could play a role in BD pathogenesis. The study also indicates an association with HLA-A*26 in German and Turkish BD patients as a genetic risk factor independent of HLA-B*51.