학술논문

HLA and autoantibodies define scleroderma subtypes and risk in African and European Americans and suggest a role for molecular mimicry
Document Type
article
Source
Proceedings of the National Academy of Sciences of the United States of America. 117(1)
Subject
Biomedical and Clinical Sciences
Immunology
Autoimmune Disease
Clinical Research
Scleroderma
Genetics
2.1 Biological and endogenous factors
Aetiology
Inflammatory and immune system
Black or African American
Alleles
Amino Acid Sequence
Antigens
Viral
Autoantibodies
Autoantigens
Computational Biology
Datasets as Topic
Female
Genetic Predisposition to Disease
HLA Antigens
Humans
Male
Mimiviridae
Molecular Mimicry
Phycodnaviridae
Protein Structure
Secondary
Risk Assessment
Scleroderma
Systemic
Sequence Homology
Amino Acid
White People
scleroderma
HLA
autoantibodies
molecular mimicry
mimivirus
Language
Abstract
Systemic sclerosis (SSc) is a clinically heterogeneous autoimmune disease characterized by mutually exclusive autoantibodies directed against distinct nuclear antigens. We examined HLA associations in SSc and its autoantibody subsets in a large, newly recruited African American (AA) cohort and among European Americans (EA). In the AA population, the African ancestry-predominant HLA-DRB1*08:04 and HLA-DRB1*11:02 alleles were associated with overall SSc risk, and the HLA-DRB1*08:04 allele was strongly associated with the severe antifibrillarin (AFA) antibody subset of SSc (odds ratio = 7.4). These African ancestry-predominant alleles may help explain the increased frequency and severity of SSc among the AA population. In the EA population, the HLA-DPB1*13:01 and HLA-DRB1*07:01 alleles were more strongly associated with antitopoisomerase (ATA) and anticentromere antibody-positive subsets of SSc, respectively, than with overall SSc risk, emphasizing the importance of HLA in defining autoantibody subtypes. The association of the HLA-DPB1*13:01 allele with the ATA+ subset of SSc in both AA and EA patients demonstrated a transancestry effect. A direct correlation between SSc prevalence and HLA-DPB1*13:01 allele frequency in multiple populations was observed (r = 0.98, P = 3 × 10-6). Conditional analysis in the autoantibody subsets of SSc revealed several associated amino acid residues, mostly in the peptide-binding groove of the class II HLA molecules. Using HLA α/β allelic heterodimers, we bioinformatically predicted immunodominant peptides of topoisomerase 1, fibrillarin, and centromere protein A and discovered that they are homologous to viral protein sequences from the Mimiviridae and Phycodnaviridae families. Taken together, these data suggest a possible link between HLA alleles, autoantibodies, and environmental triggers in the pathogenesis of SSc.