islet cell antibody (ICA) /ī′lit/ [MFr, islette, little island] , an immunoglobulin that reacts with cytoplasmic components of pancreatic islet cells. These antibodies occur in about 60% to 70% of newly diagnosed patients with insulin-dependent diabetes mellitus, providing strong evidence for an autoimmune origin and pathogenesis of the disease. The presence of ICA can be demonstrated years before the occurrence of symptoms. The antibody tends to disappear with time.
