Each of these types of AIHA may be sub-classified based on the presence or absence of underlying diseases. In the absence of an underlying disease, the AIHA is termed primary or idiopathic. When AIHA occurs as a manifestation or complication of another disease, the term secondary AIHA is used. Chronic lymphocytic leukemia (CLL) and lymphomas account for about half of all secondary AIHA cases. Systemic lupus erythematosus (SLE) and other autoimmune diseases also account for a large number of secondary AIHA cases. Certain drugs also mediate immune injury to RBCs. Three mechanisms are recognized and two of these involve elements of autoimmunity, in which autoantibodies recognize and bind to specific RBC epitopes in concert with drugs or their metabolites or in which the autoantibody binds to RBC epitopes without the presence of drug