Immunological response in diabetes mellitus.

Diabetes mellitus is a complex syndrome characterized by hyperglycaemia, thickening of basement membrane of the capillaries and a variety of late complications including accelerated atherosclerosis, retinopathy, nephropathy and neuropathy. Primary diabetes mellitus is broadly divided into type I or the insulin-dependent diabetes mellitus (IDDM) and type 2 or the non-insulin-dependent diabetes mellitus (NIDDM). There also exists a rare form of diabetes mellitus which is dominantly inherited, referred to as "maturity-onset" diabetes of the young and is distinct from the more common types of primary diabetes. IDDM has an earlier age of onset (usually less than 30 years), often rapid onset, is ketosis prone, associated with human leukocyte antigens (HLA) and highly associated with anti-islet cell immunity. NIDDM has a later age of onset (usally more than 40 years), often insidious onset, rarely leads to ketosis, is not associated with HLA and rarely, if ever, associated with antiislet cell immunity. Since IDDM is highly associated with antiislet cell immunity, some investigators have proposed two subtypes of the type 1 diabetes: type la, the more common juvenile form thought to be initiated by viruses and type 1b found in polyendocrine patients in whom viral etiology is less conspicuous and an autoimmune anomaly is likely.