Autoimmunity is a hyperactive response against self or auto-antigen. It is due to a breakdown in self-tolerance. The presence of auto- antibodies is necessary to diagnose autoimmune diseases.
The auto- antigen, auto-antibodies and the autoimmune diseases are classified to two categories; either confined to one organ or seen in more than one organ. The underlying factors for autoimmunity may be genetic, lack of suppressor cells, increased effectors T cells, presence of polyclonal B cell activators and viral infections. Diagnosis of autoimmunity includes indirect immune fluorescence, titration by agglutination technique, receptor binding assays and idiotyping. This contribution was a summarized review presenting a simple approach to understand the autoimmune process. The new classification of autoimmune diseases provides a practical framework of understanding