T-CELL RECEPTOR-ALPHA, DELTA, AND GAMMA-CHAIN GENES IN INSULIN-DEPENDENT DIABETES-MELLITUS

We have studied the genotypic, haplotypic, and allelic distribution of germline Restriction Fragment Length Polymorphism (RFLP) of T-cell re ceptor (Tcr) alpha, gamma, and delta loci in 75 insulin-dependent diab etes mellitus (IDDM) patients and 84 healthy blood donors as control p opulation. The restriction endonuclease PvuII produces three allelic f ragments of Tcr Cgamma (TcrCG) gene segment of 16, 13, and 11.3 Kb res pectively. Our observations revealed that PvuII/TcrCG RFLP allelic dis tributions were not significantly different in the IDDM and the contro l group. However, 85% of IDDM patients carried HLA DR3 and/or DR4 hapl otypes, and when comparing these patients with a second group of HLA D R3+ and/or DR4+ healthy individuals, the 11.3 Kb/PvuII fragment of Tcr CG gene was found to be associated with IDDM patients (chi2 = 11.4, P = 0.003). 54.9% of IDDM patients carried at least one 11.3 Kb allele v s. 21% in controls (chi2 = 10.77, P = 0.004). No significant associati on was found between RFLP in Tcr, Calpha, Cdelta, Vgamma9 loci and IDD M.