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[Molecular analysis of HLA-DR beta polymorphism in Han nationality patients with rheumatoid arthritis]
Insights
The human leukocyte antigen (HLA)-DR4 gene is strongly linked to rheumatoid arthritis (RA) susceptibility in the Han Chinese population. Specific amino acid sequences within HLA-DR4, particularly QKRAA or QRRAA, are key determinants of RA risk.
Area of Science:
- Immunogenetics
- Rheumatology
- Population Genetics
Background:
- Rheumatoid arthritis (RA) is a chronic autoimmune disease with a significant genetic component.
- Human Leukocyte Antigen (HLA) genes, particularly HLA-DR, are known to be associated with RA susceptibility in various populations.
Purpose of the Study:
- To investigate the molecular basis of HLA-DR associations with rheumatoid arthritis (RA) in the Han Chinese population.
- To identify specific HLA-DRB1 alleles and amino acid sequences conferring RA risk.
Main Methods:
- Utilized Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) to determine HLA-DRB1 alleles.
- Compared allele frequencies and amino acid sequence motifs between 35 RA patients and 100 healthy controls from the Han nationality.
Main Results:
- HLA-DR4 (DRB1*04) was significantly more frequent in RA patients (51.4%) than in controls (24.0%), indicating a 3.3-fold increased risk (P < 0.01).
- The amino acid sequences QKRAA or QRRAA were significantly elevated in RA patients (65.7%) compared to controls (30.0%, P < 0.001).
- Specific residue substitutions at positions 85 (V) and 86 (G) within these motifs correlated with RA risk, with multiple substitutions reducing RA incidence.
Conclusions:
- HLA-DR4 is strongly associated with rheumatoid arthritis in the Han Chinese population.
- The amino acid sequences QKRAA or QRRAA, along with specific residue variations at V85 and G86, are dominant genetic factors influencing RA susceptibility.
Objective:
To analyze the molecular basis for HLA-DR associations with rheumatoid arthritis(RA) in the han nationality of Chinese population.
Methods:
Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques were used to dertermine DRB1 alleles in 35 unrelated patients with RA and 100 healthy controls from the Han nationality.
Results:
The frequency of DR4(DRB1 * 04) was 51.4% in RA patients and 24.0% in the healthy controls(P < 0.01, RR = 3.3). There was a significant increase in the presence of the amino acid sequences QKRAA or QRRAA both in the RA patients overall compared with the healthy group(65.7% vs 30.0%, P < 0.001) and in DR4+ RA patients compared with DR4+ healthy individuals(100% vs 75.0%, P < 0.05). Substitution of residues in QKRAA, V85 and G86 appeared to correlate with relative risk for RA, among the subjects having 0-1 amino acid substitution, RA occurred in 48.8%, whereas in subjects with 2-3 amino acid changes, RA was present in only 16.7%.
Conclusion:
These results suggest that DR4 is strongly associated with RA in the Han nationality, and the dominant effect that determines susceptibility to RA is associated with QKRAA or QRRAA as well as V85 and G86.