HLA-A,-B,-C and -DR Antigens and Juvenile-Onset Diabetes Mellitus

Abstract

<p>The genetic region which exerts a major influence on graft rejection is known as the major histocompatibility complex or MHC. The MHC in man, the HLA system, includes at least five distinct multi-allelic loci, HLA-A,-B,-C,-D and -DR. The HLA system possesses three fundamental characteristics: it is highly polymorphic; its alleles are in linkage disequilibrium with one another as well as with other loci; and the HLA antigens demonstrate extensive cross-reactivity.</p> <p>A number of previous reports have established associations between certain HLA-B antigens and juvenile-onset insulin-dependent diabetes mellitus (JOD). In this investigation we have studied the distribution of HLA antigens in patients with diabetes mellitus with a special emphasis on HLA antigens belonging to the DR locus. We observed a significant increase in the incidence of HLA-DR4 in JOD patients as compared to its frequency in the normal controls. The present data also confirm earlier reports of the increased incidence of HLA-B15, -B40 and -CW3 in the patient group. Further analyses of the data showed that the primary association of JOD was with HLA-DR4 and the associations with the HLA-B and -C loci antigens were secondary in nature.</p>