Autoimmune hemolytic anemia

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Overview
Autoimmune hemolytic anemia (AIHA) is a type of hemolytic anemia where the body's immune system attacks its own red blood cells (RBCs), leading to their destruction (hemolysis). Antibodies and associated complement system components become fixed onto the RBC surface. These antibodies can be detected with the direct antiglobulin test, also known as the direct Coombs test. AIHA can also be induced by several drugs including methyl-dopa and fluarabine.

Autoimmunity must not be confused with alloimmunity.

Classification
Haemolysis can be intravascular or extravascular.

Intravascular haemolysis Red blood cell lysis occurs in the circulation as a result of activation of the complement system cascade. Extravascular haemolysis Red Blood Cells that are coated with antibodies are specifically recognised in the reticuloendothelial system and destroyed by macrophages.

Subtypes

 * Warm antibody autoimmune hemolytic anemia
 * Idiopathic
 * Systemic lupus erythematosus
 * Evans' syndrome (antiplatelet antibodies and haemolytic antibodies)
 * Chronic lymphocytic leukemia
 * Drugs (methyldopa)


 * Cold antibody autoimmune hemolytic anemia
 * Idiopathic cold hemagglutinin syndrome
 * Infectious mononucleosis
 * Paroxysmal cold hemoglobinuria (rare)
 * Lymphoma


 * Mixed-type autoimmune hemolytic anemia

Laboratory findings

 * Positive direct Coombs test
 * Anaemia

Related chapters

 * Haematology
 * Haemolytic anaemia

Autoimmunhämolytische Anämie Anemia inmunohemolítica Anemia hemolítica auto-imune