Autoantibodies in human diabetes.

A shared attribute of many autoimmune diseases is a humoral response directed against multiple target antigens [1, 2]. The immunological diagnosis of autoimmune diseases relies mainly on the detection of autoantibodies in the serum of patients [3]. Although their pathogenic significance is still unclear, they have the great advantage of serving as constitutive markers for specific autoimmune responses. They are also important tools for the molecular cloning, identification and characterization of novel autoantigens [4, 5]. Cloned autoantigens represent an unlimited source of reagents that can be used for experimental and diagnostic purposes. In addition to studying the immunological properties of autoantigens, these molecules can readily be utilized to optimize fluid-phase radioimmunoassays [6], which in turn have future diagnostic purposes [7, 8]. For some diseases, such as autoimmune diabetes, autoimmune connective tissue diseases, systemic lupus erythematosus (SLE), autoimmune thyroid disease (AITD), rheumatoid arthritis (RA) and other chronic systemic autoimmune diseases, recombinant proteins can be utilized to devise some of the most sensitive and specific biochemical assays currently available for autoantibody detection [5, 9]. In the majority of chronic autoimmune disorders for which a diagnosis has been established, antibody laboratory testing is instrumental in decision-making for disease management based on the identification of disease activity. Autoantibodies are some of the most potent risk determinants for autoimmune diseases with relative risk exceeding 100 [10–12]. The quintessential model for the application of autoantibody markers in the prediction of a selective immune-mediated tissue damage is type 1 diabetes (T1D) and this concept