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HLA-DQ6-mediated protection in IDDM
1Karolinska Institute, Department of Molecular Medicine, Karolinska Hospital, Stockholm, Sweden. sanjeevi.carani@molmed.ki.se
Human Immunology
|March 16, 2000
Summary
Human leukocyte antigen DQ (HLA-DQ) alleles like DQ8 and DQ2 are linked to type 1 diabetes risk, while certain DQ6 alleles offer protection, particularly in younger individuals. Molecular modeling reveals key residues and electrostatic potentials influencing this association.
Area of Science:
- Immunogenetics
- Molecular biology
- Human genetics
Background:
- Type 1 diabetes (T1D) is an autoimmune disease with a known genetic component.
- Human leukocyte antigen (HLA) genes, particularly HLA-DQ, are strongly associated with T1D susceptibility and resistance.
Purpose of the Study:
- To investigate the association of specific HLA-DQ alleles with T1D in Swedish Caucasians.
- To explore the structural and physicochemical basis for the observed HLA-DQ associations with T1D.
Main Methods:
- Case-control study analyzing HLA-DQ allele frequencies in T1D patients and controls.
- Three-dimensional molecular modeling of HLA-DQ molecules to analyze structural features and electrostatic potentials.
Main Results:
- Positive associations found for DQ8, DQ2, and DQ6 (DQB1*0604).
- Negative associations (protection) found for DQ6 (DQB1*0602, DQB1*0603) and DQ7.
- Protective effect of DQ6 (DQB1*0602) is age-dependent, stronger in younger individuals.
- Structural analysis identified key residues (57 and 70) in DQB1*0602 and DQB1*0604.
- Positively associated DQ molecules exhibit distinct surface electrostatic potentials compared to negatively associated molecules.
Conclusions:
- Specific HLA-DQ alleles influence T1D risk and protection in Swedish Caucasians.
- Molecular structure, particularly residue variations and surface electrostatic potentials, plays a critical role in HLA-DQ mediated T1D associations.