HLA-B27 Subtypes Distribution among Moroccan Patients with Ankylosing Spondylitis

Abstract

The association of HLA-B27 with ankylosing spondylitis accounts for 20 to 50% of the total disease risk. It varies markedly among racial and ethnic populations. The main purpose of the present study is to perform an investigation regarding the distribution of the human leukocyte antigen HLA-B27 and its subtypes in Moroccan healthy controls and in patients with AS and to compare this with other reports from other populations. One hundred twenty-five controls and 116 patients with AS were evaluated in this study. Among patients, three cases were associated to acute anterior uveitis. Typing of the HLA-B27 alleles was performed by microlymphocytotoxicity and polymerase chain reaction amplification with sequence-specific primers. A significant association between ankylosing spondylitis and B27 was identified; HLA-B*27 allele was carried by 46.5% of patients and only one subject from healthy controls was found to be positive (p<0.001, RR= 2.95). Among all positive patients, 64.8% were males and 53.7% belonged to 20-29 and 30-39 age groups. Being male aged 30-39 was significantly associated with B27 positivity. Four HLA-B*27 alleles were observed in this study: B*2705 (44.4%), B*2702 (29.6%), B*2703 (9.2%) and B*2708 (16.7%). The only positive subject from healthy controls carried B*2705 allele. B*2708 subtype was identified in all cases with uveitis. This allele showed a significant association with patients being female. Concluding, HLA-B27 is strongly associated with ankylosing spondylitis in Moroccan population. Our results showed a restricted number of HLA-B27 subtypes with predominance of HLA-B*2705, 02 alleles. The B*2708 allele detected for the first time in North Africa, seems to be associated with ankylosing spondylitis in the studied population.

Polymorphisms of HLA‐A, ‐B, ‐Cw and DRB1 antigens in Moroccan patients with ankylosing spondylitis and a comparison of clinical features with frequencies of HLA‐B*27

“…HLA-B27 was the most frequent allele associated with AS and was positive in 64% of Moroccan AS patients, suggesting that this gene is involved in the predisposition of the disease in our population. When compared to other data in the literature, this prevalence was higher to the 46.5% and 29% prevalences reported in previous Moroccan AS patients studies (16,19) and lower to the prevalences reported in European populations: 94.3% in Spanish AS patients (26), 90.2% in British AS patients (46), 90% in Greek AS patients (47), and 90.2% in Turkish AS patients (48). This difference in frequencies suggests that different genes not belonging to HLA-B27 and/or environmental factors may be involved in AS etiopathogenesis.…”

“…Recently, Amribet et al identified only four HLA‐B*27 variants: B*2705, B*2702 , B*2703 , and B*2708 , among which B*2705 and B*2702 were the most frequent subtypes, in 54 Moroccan AS patients positive for B*27 . Furthermore, they identified only one HLA‐B2705 among 100 healthy controls . Previously, Gonzales‐Rocec et al found that in a small group (37 cases) of AS patients, only two B*27 ( B*2705 and B*2702 ) with the same frequency .…”

“…HLA B*2702 was the second frequent allele in our patients (20.8%) and clearly disease associated. This allele is represented in high frequency in the Middle Eastern Arabs and Berbers . It is present in 51.7%–73.8% of B27 positive individuals of North‐East European region and around 54% in Jewish populations , in contrast to 10%–20% in Southern‐western European populations such as French , Croatian , and Spanish where HLA B*2705 is commonly found.…”

Impact of HLA -B*27 subtypes with increased susceptibility to seronegative spondyloarthropathies in Vojvodina population

“…This allele is present in 4-10% of B27 positive individuals of Northern Europe, 20% in Spain and Portugal and about 55% in Arab and Jewish populations (NICKMAN et al, 2008). It is prevalent in Mediterranean populations, showing a high frequency in the Middle Eastern Arabs and Berbers (MERYEM et al, 2013). The HLA-B*27 alleles detected in this study are the alleles shared by both Europeans and North Asian populations , and no contribution of others confined to the Middle East and West Asian populations (HLA-B*27:07), West Africans (HLA-B*27:03), and North Europeans (HLA-B*27:08) (ERMANN, 2016), confirming a strong Euro-Caucasoid (Aryan) component in the population of Vojvodina.…”

Diversity in HLA class I and class II in kidney donors and recipients according to race in KwaZulu-Natal (South Africa) implications for transplantation

“…The association of HLA and diseases are widely reported [9][10][11][12]. Certain HLA antigens have been associated with renal disease and cardiovascular diseases, especially certain phenotypes are associated with cardiovascular hypertrophy [13,14].…”