Distribution of Major HLA-A, -B, -DR, and -DQ Loci Potentially Associated with Multiple Sclerosis in a Healthy Population from Southern Morocco

Many factors contribute to the development and the progression of Multiple Sclerosis (MS), including Human Leukocyte Antigen (HLA) molecules. Some of them are considered as predisposing, like DRB1*15, DRB1*13, DRB1*03, DRB1*04, DQB1*06, DQB1*02, while HLA A2, HLA B44, DRB1*11, and DRB1*12 are rather considered as protective. Data about such associations in the Moroccan population remain unknown. The aim of this study was to determine the frequency of HLA class I (A and B) and II (DR and DQ) linked to Multiple Sclerosis (MS) in a healthy population from the South of Morocco. A cross-sectional study was carried out over the 2016-2023 period on 685 Moroccan healthy individuals, including 355 males and 330 females. Of the total sample tested, 685 underwent HLA class I typing, of which 305 also benefited from HLA class II typing. HLA class I typing was executed using the CDC (complement dependent cytotoxicity) technique (OneLambda™, Los Angeles CA, USA), and HLA class II typing was performed by either PCR-SSP (sequence-specific primer, OneLambda) or PCR-SSO (sequence-specific oligonucleotides) using the Luminex Xmap (Lifecodes, Immucor, Peachtree, Corners, GA, USA) system. From different HLA molecules potentially predisposing to MS, our investigations showed that DRB1*03, DRB1*13, DRB1*15, DRB1*04, and DQB1*02 were observed in 19.2%, 15.8%, 13.31%, 12.7% and 31% respectively, while the frequency of those considered as protective, namely HLA-A2, HLA-B44, and HLA-DRB1*11 was 23.31%, 9.21% and 10.1% respectively. The findings of our study give evidence that among predisposing HLA class II molecules, DR allele groups were more prevalent, mostly DRB1*03, with also a high frequency of DQB1*06, while HLA-A2 marked the supposed protective specificities. These results need to be supported by complementary studies particularly in MS patients.