[Immunologic mechanisms implicated in autoimmune destruction of beta cells in type I diabetes].

Lymphocytic infiltration of the islets of Langerhans results from activation of immunity effector cells during the period preceding clinical onset of diabetes. After escape from thymic selection, the autoreactive cell clones proliferate in the peripheral hemopoietic organs prior to invading the islets of Langerhans. The selection, expansion and activation of autoreactive cells are under genetic control. The development of quantitative tests of cellular immunity should allow determination of the importance of the anti-islet immunologic reaction, suspected at present from the presence of specific autoantibodies in genetically predisposed subjects at high risk of insulin dependence.