Autoantibodies are those Antibodies that are Specific to those antigens which are normally tolerated by the immmune syste and are typically constituents of cells and tissues of the animal in question such antigens are called autoantigens. Autoantibodies are produced in conditions of autoimmunity, which may be simply described an attack by the immune system on the host itself the antibodies are either cell specific or non organ specific they recognise variety of cellular and subcellular components including the components of replicon transcription RNA processing RNA translation and protein processing. The antigenic specific of antibodies can be useful in clinical diagnosis of the associated autoimmune disease.