Autoimmune Hemolytic Anemia (AIHA) is an immune system disorder in which a person’s own antibodies attack and destroy the red blood cells in his or her body. The destruction of red blood cells leads to anemia, which can cause fatigue, paleness, and shortness of breath. AIHA is further classified as either warm or cold, depending on the temperature at which the antibodies most efficiently attack the red blood cells.
Warm Autoimmune Hemolytic Anemia
In warm AIHA, the antibodies work best at body temperature and can cause hemolysis (destruction of red blood cells) to occur most efficiently at 37°C. This type of AIHA is more common and is usually caused by a polyclonal B-cell activation, which can be triggered by certain medications, infections, or other diseases. Symptoms of warm AIHA include fatigue, jaundice, and an enlarged spleen.
Cold Autoimmune Hemolytic Anemia
In cold AIHA, the antibodies work best at cold temperatures and cause hemolysis to occur most efficiently at 4°C. This type of AIHA is less common and is usually caused by an underlying autoimmune disorder such as systemic lupus erythematosus, Sjögren’s syndrome, or rheumatoid arthritis. Symptoms of cold AIHA include fatigue, jaundice, and dark urine.
The treatment of warm and cold AIHA is similar and usually includes corticosteroids, intravenous immunoglobulin, and rituximab. In some cases, splenectomy (surgical removal of the spleen) may be recommended.
