Cell-mediated immunity and immune complexes in the pathogenesis of type 1 (insulin-dependent) diabetes.

Evidence for a role of the immune system in the pathogenesis of insulin-dependent (Type 1) diabetes is now plentiful. In the light of the lymphocytic infiltration in the islets of Langerhans, different autoaggressive mechanisms have been suggested in the initiation of B-cell damage. Lymphocytes characterized by cytotoxic properties (K cells) and having receptors for the Fc of IgG are increased in newly diagnosed Type 1 diabetics. Circulating immune complexes are also raised in these patients at the time of clinical diagnosis and there is evidence that K cells bind immune complexes which can modulate the activity of these cells. Here we propose a possible interrelationship between K or Fc gamma receptor+ T lymphocytes and immune complexes which could have a 'key' role in the mechanism of activation of cell-mediated immunity towards B-cells.