Immune mechanisms leading to type 1 insulin-dependent diabetes mellitus.

Insulin-dependent diabetes mellitus (IDDM) results from the autoimmune destruction of the endocrine (beta) cells responsible for the secretion of insulin. Experimental and human studies have resulted in unpredicted developments over the past ten years. Against most predictions, a long list of possible autoantigens has been defined, most of which are not beta-cell specific. Seemingly, up to 10 to 20 genetic regions, rather than 2 to 3 as initially predicted, carry markers that associate them with IDDM. Finally, there is accumulating evidence that beta cells are not a passive bystander in the event that leads to the activation of the diabetes autoimmune reaction. Whether the immune system or the islet, or both, are at the initiation of the disease process is a challenge for the near future.