HLA-D region β-chain DNA endonuclease fragments differ between HLA-DR identical healthy and insulin-dependent diabetic individuals
Summary, in English
The human HLA-D histocompatibility region encodes class II antigens each of which consists of two polypeptide chains (α and β) inserted in the plasma membrane. These molecules are implicated in the regulation of the immune response1-3 but several human diseases are also found to be associated with certain HLA-DR antigens4. The occurrence of insulin-dependent (type I) diabetes (IDDM) is strongly associated with HLA-DR3 and/or 4 (ref. 5). The class II antigens, however, show a marked genetic polymorphism1 associated with the β-chains6,7 which seem, from hybridization studies, to be encoded by several genes8,9. We have therefore used the β-chain cDNA probe, pDR-β-1 (refs 8, 10) to test whether there are differences in hybridization pattern between DNA from healthy individuals and diabetic patients, after digestion with restriction endonucleases. Among the HLA-DR 4 and 3/4 individuals, the IDDM patients showed an increased frequency of a PstI 18 kilobase (kb) fragment. A BamHI 3.7 kb fragment, frequent among controls (30-40%), was rarely detected in the IDDM patients (0-2%). These differences may be related to susceptibility to develop the disease.