AB1026 INFLAMMATORY MANIFESTATIONS IN PATIENTS WITH HUMAN LEUKOCYTE ANTIGEN-B*51 POSITIVE AND WITHOUT BEHÇET’S DISEASE
Authors: M. Duarte, J. Sousa Morais, R. Faria, B. Guerra Leal, A. Marinho, J. Correia, F. Farinha, P. Pinho Costa, B. Martins Da Silva, C. Vasconcelos
Journal: Annals of the Rheumatic Diseases (2020)

Background: Human leukocyte antigen (HLA) B*51 allele is the most important genetic factor in susceptibility to Behçet’s disease (BD), an immune-mediated systemic disorder of unknown etiology, characterized by recurrent episodes of inflammatory manifestations. In fact there is a considerable clinical overlap of BD with autoinflammatory syndromes. As it’s known, the majority of HLA-B*51 positive individuals do not develop BD. But do these individuals also present inflammatory manifestations? Objectives: Characterize the group of individuals in our hospital with positive HLA-B*51, without BD diagnosis and review whether inflammatory manifestations are present in these individuals. Methods: A retrospective study of HLA-B*51 positive patients between 2000 and 2019. Genomic DNA was obtained from peripheral blood and HLA genotyping was performed using a PCR with Sequence Specific Primers (PCR–SSP) methodology. From the group of 289 B*51 positive patients, BD diagnosis were excluded. Demographic and clinical data were collected by review of clinical files in December 2019. Results: 176 patients, mean age of 48.5 ± 16.5 years (5 to 84 years). Most were female (68%). The HLA study was motivated by multiple diagnostic suspicions: spondyloarthritis (SpA, 25.0%), BD (22.7%) and systemic sclerosis (SSc, 10.8%). The mean time elapsed since the immunogenetic study was 8.3 years, with 12 deaths recorded. 69 (39.2%) subjects had no diagnosis for immune-mediated disease (IMD). Of the other 107 patients, the majority had 1 IMD (64.5%), and the rest were diagnosed with 2 to 4 IMD. The most frequent IMD were SpA (20.8%), psoriasis (10.4%), psoriatic arthritis (9.7%), SSc (9.7%) and rheumatoid arthritis (7.1%). Autoantibodies were detected in 94 individuals (53.4%): antinuclear antibodies (64 patients), rheumatoid factor (26 patients) and CCP antibodies (11 patients). In 55 individuals no inflammatory manifestation was identified but the 68.8% of them presented between 1 to 7 manifestations: System involved Clinical manifestation Frequency Ears, nose and throat Chronic rhinitis 32 (13.2%) ∑ = 76 (31.4%) Recurrent tonsillitis 20 (8.3%) Other 24 (9.9%) Cutaneous, mucous and serous Recurrent oral aphtous ulcers 34 (14.0%) ∑ = 57 (23.6%) Serositis 10 (4.1%) Other 13 (5.4%) Neurological Chronic headache 34 (14.0%) ∑ = 36 (14.9%) Asseptic meningitis 2 (0.8%) Ocular Ocular inflammation 31 (12.8%) ∑ = 31 (12.8%) Urinary Recurrent cystitis 15 (6.2%) ∑ = 15 (6.2%) Vascular Venous thromboembolism 7 (2.9%) ∑ = 14 (5.8%) Aneurysm 6 (2.5%) Spontaneous coronary dissection 1 (0.4%) Rheumatic Arthromyalgia 6 (2.5%) ∑ = 9 (3.7%) Gout 3 (1.2%) Constitutional Recurrent fever syndrome 1 (0.4%) ∑ = 1 (0.4%) Digestive Recurrent abdominal pain 1 (0.4%) ∑ = 1 (0.4%) Lymphatic Axillary and inguinal adenopathies 1 (0.4%) ∑ = 1 (0.4%) Pulmonary Chronic pulmonary infiltrate 1 (0.4%) ∑ = 1 (0.4%) Conclusion: Inflammatory manifestations are common in HLA-B*51 positive individuals, even in those without BD diagnosis. Further research is needed, considering other HLA alleles associated with increased risk of BD and including control groups. References: [1]Burillo-Sanz S, Montes-Cano M, García-Lozano J, et al . Behçet´s disease and genetic interactions between HLA-B*51 and variants in genes of autoinflammatory syndromes. Sci Rep 2019;9:2777. [2]McGonagle D, McDermott MF. A Proposed Classification on the Immunological Diseases. PLoS Med 2006;3(8):e297. [3]Tong B, Liu X, Xiao J, Su G. Immunopathogenesis of Behcet´s Disease. Front. Immunol 2019;10:665. Disclosure of Interests: None declared