Lack of an association between polymorphisms of the T-cell receptor alpha-chain and ulcerative colitis.

It was recently reported that, using a T-cell receptor alpha-chain complementary deoxyribonucleic acid probe (pGA5) and the restriction enzyme Eco RV, a 10-kilobase restriction fragment length polymorphism was detected significantly more frequently in patients with ulcerative colitis than in patients with Crohn's disease and controls. This finding had great potential importance, as no gene marker had previously been found to be strongly associated with inflammatory bowel disease. Therefore, an attempt to confirm it in an independent laboratory and patient population has been made in this study. Thirty patients with ulcerative colitis, 30 with Crohn's disease, and 30 healthy control subjects were studied using the Eco RV restriction enzyme and the same T-cell receptor alpha-chain complementary deoxyribonucleic acid probe as was used in the prior report. No 10-kilobase fragment or any other polymorphism using this probe-enzyme combination was found in any of the individuals studied. Polymorphisms were observed with the restriction enzyme Bgl II, but their frequencies did not distinguish between cases and controls. Therefore, there is as yet no evidence for an association between polymorphisms of Eco RV-digested genomic DNA probed with the pGA5 T-cell receptor alpha-chain complementary deoxyribonucleic acid and the predisposition to inflammatory bowel disease.