AB0856 Prevalence of HLAB27 antigen in Moroccan patients with spondyloarthritis (SpA): a multicenter study

Abstract

BackgroundSpondyloarthritis includes an heterogeneous group of rheumatisms characterized by their strong association with HLA-B27 (1). The association between SpA and HLA-B 27 is one of the strongest known associations between an HLA allele and disease (2). Several studies have highlighted the importance of this association for diagnosis, predicting disease phenotype and prognosis of spondyloarthritis (SpA) (1.2).ObjectivesThe aim of the present study is to determine the prevalence of HLAB27 in Moroccan SpA patients and to analyze the correlation between HLAB27 status and different disease parameters.MethodsIt is a multicenter cross-sectional study including 256 SpA patients. Demographic, clinical, paraclinical and therapeutic parameters of the disease were collected. Disease activity was assessed by BASDAI and ASDAS-CRP scores. Patients were classified into two groups: HLAB27(+) and HLAB27(-). A comparison regarding HLA-B27 status was performed using the Mann-Whitney and Chi2 T-student tests. The significance threshold was set at p<0.05.Results256 SpA patients were included in the study, 241 patients have HLAB27 status of which 114 (44.5%) were HLAB27-positive. 46.6% of men and 40.9% of women were HLAB27-positive. 233 patients had axial SpA of which 110 patients (47.21%) were HLAB27-positive. The mean age was 39.58 ±12.89 years. The HLAB27-positive group had a longer diagnostic delay (p= 0.008) with a mean of 4 years. 46 patients had a family history of SpA of which 25.4% were HLAB27-positive and 11.8% HLAB27-negative (p=0.007). The HLAB27-positive patients had more axial manifestations (96.5% vs. 85.9%; p=0.01). While peripheral involvement was more noted in the HLAB27-negative group (90.6% vs 35.1%; p<0.001). Enthesopathy was more observed in the HLAb27-positive group (78% vs 62.2%; p=0.001). HLAB27-positive patients had more active disease defined by ASDAS-CRP (3.13±1.23 vs. 2.24±1.14; p<0.001). Only one case of uveitis was noted in the HLAb27-negative group versus 27 cases in the HLAB27-positive group (p<0.001). 33 HLAB27-positive patients had radiographic coxitis (33 vs16, p=0.002). The bDMARDS were more prescribed in the HLAB27-positive patients (58.8% vs 35.4%; p=0.009).ConclusionIn our study, the prevalence of HLAB27 was close to the MENA region (3). The presence of HLAB27 is related to an earlier disease onset, higher activity, to the presence of coxitis and uveitis and consequently more use of biotherapy in this group (HLAB27-positive).References[1]Arévalo M, Gratacós Masmitjà J, Moreno M, Calvet J, Orellana C, Ruiz D, Castro C, Carreto P, Larrosa M, Collantes E, Font P; REGISPONSER group. Influence of HLA-B27 on the Ankylosing Spondylitis phenotype: results from the REGISPONSER database. Arthritis Res Ther. 2018 Oct 3;20(1):221.[2]Kavadichanda CG, Geng J, Bulusu SN, Negi VS, Raghavan M. Spondyloarthritis and the Human Leukocyte Antigen (HLA)-B*27 Connection. Front Immunol. 2021 Mar 8;12:601518.[3]Slimani S, Hamdi W, Nassar K, Kalla AA. Spondyloarthritis in North Africa: an update. Clin Rheumatol. 2021 Sep;40(9):3401-3410.Disclosure of InterestsNone declared