[Does insulitis have importance in the pathogenesis of type-1 diabetes in man?]

Insulitis is a lymphocytic infiltration of islets of Langerhans occurring together with a selective loss of beta cells. Infiltrating cells spread from peripheral islet vessels to the centre of a given islet. In humans, insulitis is believed to be associated with autoimmune phenomena, e.g. autoantibodies to beta cells. Insulitis is seen in IDDM of man with young age of onset and short duration of disease. In animal models, insulitis is not necessarily associated with autoimmunity. From animal studies it is known that insulitis does not always end up with manifestation of diabetes in a given animal. Experimental data provide evidence for a dysregulated immune system recognizing beta-cell-specific antigens and producing beta-cell-cytotoxic lymphocytes. On the other hand, the surface of the beta cell changes induced by viral infection or environmental toxins and thereby becomes the target of an immune attack.