Two HLA class I genes independently associated with multiple sclerosis.

Area of Science:

• Immunogenetics
• Neuroimmunology
• Human Genetics

Background:

• The human leukocyte antigen (HLA) system plays a critical role in immune response and is implicated in autoimmune diseases like multiple sclerosis (MS).
• While HLA-DRB1 is a known risk factor for MS, the specific contributions of HLA class I alleles remain incompletely understood.
• Previous research suggested potential protective roles for HLA-A*02 and HLA-C*05 in MS susceptibility.

Purpose of the Study:

• To comprehensively investigate the role of HLA class I alleles in modulating the risk of multiple sclerosis (MS).
• To identify specific HLA class I alleles associated with MS susceptibility or protection.
• To elucidate the independent contributions of different HLA genes within the class I region.

Main Methods:

• Genotyping of HLA-DRB1, HLA-A, and HLA-C alleles was performed in a cohort of 1529 MS patients and 1814 controls from Sweden and Norway.
• Logistic regression analysis was employed for simultaneous assessment of all alleles.
• Statistical models were adjusted for potential confounding factors to ensure robust findings.

Main Results:

• Independent genetic effects were observed for HLA-DRB1, HLA-A, and HLA-C genes.
• The previously reported protective association of HLA-A*02 was confirmed (Odds Ratio [OR]=0.73, p=9.2 x 10⁻⁴).
• A novel association was identified for HLA-C*08, indicating an increased risk of MS (OR=1.85, p=0.0093).

Conclusions:

• The HLA class I region harbors at least two distinct genetic factors that influence MS risk.
• These factors are characterized by independent associations with specific alleles of the HLA-A and HLA-C genes.
• The findings highlight the complex genetic architecture of MS susceptibility within the HLA locus.