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Mixed AIHA occurs in less than 10% of cases of AIHA, whose annual incidence is between 1/35,000-1/80,000 in North America and Western Europe.

Mixed AIHA can occur at any age but is rare in children. Patients with mixed AIHA usually present with abrupt onset severe hemolysis and anemia.

Mixed AIHA can be idiopathic or secondary, mainly associated with systemic lupus erythematosus (SLE) and lymphoma.

Diagnosis is based on clinical or laboratory evidence of hemolytic anemia and the detection of autoantibodies, usually both IgG and IgM, with the direct anti-globulin test (DAT) showing a pattern of IgG with complement C3, and the presence of cold agglutinins (IgM) in the serum at a significant titer.

Erroneous diagnosis of mixed AIHA is sometimes made on the basis of inadequate serologic studies as a large proportion of patients with warm AIHA also have cold autoantibodies that are measured but are clinically insignificant. Unless a cold autoantibody with a high thermal amplitude (>30 degrees C) is observed in association with a warm autoantibody, a diagnosis of mixed AIHA is not warranted.

The principles of management are comparable to that of warm AIHA (see this term), including corticosteroids and, if these are ineffective, splenectomy, but avoidance of cold must also be considered. Cautious transfusion is possible in cases with severe anemia. However, the best compatible or ``least incompatible'' packed red blood cell units must be identified by the blood centre to avoid post-transfusional hemolysis.

The disease responds to corticosteroids, and may be followed by remission, but usually runs a chronic course with intermittent exacerbations.