T‐cell receptor β‐chain DNA polymorphism frequencies in healthy HLA‐DR homozygotes

Abstract
In view of numerous recent reports of T-cell receptor (TCR) .beta.-chain/disease associations with HLA-associated diseases, we tested the possibilities that associations might exist directly between these two gene complexes at the level of the germline DNA. We determined frequencies of five TCR-.beta. DNA polymorphisms in 33 HLA-DR2/2 homozygotes, 29 HLA-DR3/3 homozygotes and 42 HLA-DR4/4 homozygotes. The control population (n = 74) was chosen without "bias toward" their HLA-DR genes. We selected DR2, DR3 and DR2 homozygotes because they have been the most frequently involved in HLA-DR associated diseases. Our results indicate that the recent reports in the literature of TCR-.beta./disease associations can not be explained by a significantly different distribution of TCR-.beta. genes in HLA-DR2+, -DR3+ or -DR4+ subpopulations. Our results also suggest that if co-evolution between TCR-.beta. and MHC haplotypes does exist, the selective pressures in recent generations have not be strong enough to significantly alter the germline TCR-.beta. gene frequencies in HLA-DR2+, -DR3+, or -DR4+ subpopulations.