T-cell antigen receptor alpha chain polymorphisms in insulin-dependent diabetes

Area of Science:

• Immunology
• Genetics
• Endocrinology

Background:

• Insulin-dependent diabetes (Type 1 diabetes) is an autoimmune disease.
• T cells are implicated in the pathogenesis of autoimmune diabetes.
• The T-cell antigen receptor (TCR) alpha chain plays a role in T cell function.

Purpose of the Study:

• To investigate the association between the T-cell antigen receptor alpha chain and autoimmune diabetes.
• To examine TCR alpha chain polymorphisms in human Type 1 diabetes and in the BB rat model.
• To determine if TCR alpha chain variations are linked to diabetes or lymphopenia in BB rats.

Main Methods:

• Population study in humans using restriction fragment length polymorphism (RFLP) analysis of the TCR alpha chain gene.
• RFLP analysis of the TCR alpha chain in diabetic BB rats and control BBN rats.
• Breeding studies in BB and BBN rats to assess linkage between diabetes, lymphopenia, and TCR alpha chain haplotypes.

Main Results:

• No association was found between TCR alpha chain RFLPs and Type 1 diabetes in humans.
• Distinct TCR alpha chain haplotypes were identified in BB and BBN rats.
• No linkage was observed between autoimmune diabetes or lymphopenia and the TCR alpha chain in BB rats.

Conclusions:

• The T-cell antigen receptor alpha chain is not linked to autoimmune diabetes in the BB rat model.
• TCR alpha chain constant region polymorphisms are not associated with Type 1 diabetes in humans.
• These findings suggest that other genetic factors are involved in the development of autoimmune diabetes.