Immunology of diabetes mellitus

Insulin-dependent diabetes is an autoimmune disease that may be becoming more prevalent. It has a polygenic mode of inheritance with a major gene being present in the HLA DQ locus on chromosome 6. Inferential data suggest that environmental factors may be important to genetic penetrance albeit we still lack proof for involvement of often maligned viruses. Patients with IDD and their families are predisposed to organ-specific autoimmunities which should be routinely screened for. Autoantibodies to insulin, to a beta cell cytoplasmic lipid containing moiety and to a beta cell protein of 64KDa, which is believed to be the GABA forming enzyme GAD, can be used to predict IDD among relatives and probably the general population as well. Immunosuppressive therapy can modify the course of IDD after diagnosis and should be able to delay the clinical onset if given before diagnosis. Rigorous insulin therapy should also be given as needed to control hyperglycemia and avoid glucose toxicity to the islets. Such trials are now underway.