Autoimmune hemolytic anemia: Difference between revisions
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Red Blood Cells that are coated with antibodies are specifically recognised in the [[reticuloendothelial system]] and destroyed by [[macrophages]]. | Red Blood Cells that are coated with antibodies are specifically recognised in the [[reticuloendothelial system]] and destroyed by [[macrophages]]. | ||
==Subtypes== | ===Subtypes=== | ||
*'''[[Warm antibody autoimmune hemolytic anemia]]''' | *'''[[Warm antibody autoimmune hemolytic anemia]]''' | ||
Revision as of 19:57, 25 July 2012
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| Autoimmune hemolytic anemia | |
| ICD-10 | D59.0-D59.1 |
|---|---|
| ICD-9 | 283.0 |
| MedlinePlus | 000579 |
| MeSH | D000744 |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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.
Historical perspective
"Blood-induced icterus" produced by the release of massive amounts of a coloring material from blood cells followed by the formation of bile was recognized and described by Vanlair and Masius' in 1871. About 20 years later, Hayem distinguished between congenital hemolytic anemia and an acquired type of infectious icterus associated with chronic splenomegaly. In 1904, Donath and Landsteiner suggested a serum factor was responsible for hemolysis in paroxysmal cold hemoglobinuria. French investigators led by Chauffard stressed the importance of red-cell autoagglutination in patients with acquired hemolytic anemia. In 1930, Lederer and Brill described cases of acute hemolysis with rapid onset of anemia and rapid recovery after transfusion therapy. These hemolytic episodes were thought to be due to infectious agents. A clear distinction between congenital and acquired hemolytic anemia was not drawn, however, until Dameshek and Schwartz in 1938, and in 1940, they demonstrated the presence of abnormal hemolysins in the sera of patients with acquired hemolytic anemia and postulated an immune mechanism.
During the past three decades, studies defining red-cell blood groups and serum antibodies have produced diagnostic methods that have laid the basis for immunologic concepts relevant to many of the acquired hemolytic states. Of these developments, the antiglobulin test described by Coombs, Mourant, and Race in 1945 has proved to be one of the more important, useful tools now available for the detection of immune hemolytic states. This technique demonstrated that a rabbit antibody against human globulin would induce agglutination of human red cells "coated with an incomplete variety of rhesus antibody". C. Moreschlit had used the same method in 1908 in a goat antirabbit-red-cell system. The test was historically premature and was forgotten. In 1946, Boorman, Dodd, and Loutit applied the direct antiglobulin test to a variety of hemolytic anemias, and laid the foundation for the clear distinction of autoimmune from congenital hemolytic anemia.
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
- Idiopathic
- Systemic lupus erythematosus
- Evans' syndrome (antiplatelet antibodies and haemolytic antibodies)
- Chronic lymphocytic leukemia
- Drugs (methyldopa)
- Cold antibody autoimmune hemolytic anemia
- Mixed-type autoimmune hemolytic anemia
Causes
The causes of AIHA are poorly understood. The disease may be primary, or secondary to another underlying illness. The primary illness is idiopathic (the two terms being used synonymously). Idiopathic AIHA accounts for approximately 50% of cases.[1] Secondary AIHA can result from many other illnesses. Warm and cold type AIHA each have their own more common secondary causes. The most common causes of secondary warm-type AIHA include lymphoproliferative disorders (e.g. chronic lymphocytic leukemia, lymphoma) and other autoimmune disorders (e.g. systemic lupus erythematosis, rheumatoid arthritis, scleroderma, ulcerative colitis). Less common causes of warm-type AIHA include neoplasms other than lymphoid, and infection. Secondary cold type AIHA is also primarily caused by lymphoproliferative disorders, but is also commonly caused by infection, especially by mycoplasma, viral pneumonia, infectious mononucleosis and other respiratory infections. Less commonly, it can be caused by concomitant autoimmune disorders.[2]
Drug-induced AIHA, though rare, can be caused by a number of drugs, including α-methyldopa and penicillin. This is a type II immune response in which the drug binds to macromolecules on the surface of the RBCs and acts as an antigen. Antibodies are produced against the RBCs, which leads to complement activation. Complement fragments, such as C3a, C4a and C5a, activate granular leukocytes (e.g. neutrophils), while other components of the system (C6, C7, C8, C9) can either form the membrane attack complex (MAC) or can bind the antibody, aiding phagocytosis by macrophages (C3b). This is one type of "penicillin allergy".
Laboratory findings
- Positive direct Coombs test
- Anaemia
Treatment
Much literature exists regarding the treatment of AIHA. Efficacy of treatment depends on the correct diagnosis of either warm or cold type AIHA.
Warm type AIHA is usually a more insidious disease, not treatable by simply removing the underlying cause. First line therapy for this is usually with corticosteroids, such as prednisolone. Following this, other immunosuppressants are considered, such as rituximab, danazol, cyclophosphamide, azathioprine or cyclosporine.
Cold agglutinin disease is treated by avoiding the cold or sometimes with rituximab. Removal of the underlying cause is also important.
Paroxysmal cold hematuria is treated by removing the underlying cause, such as infection.
Related chapters
Template:Hematology Template:SIB
de:Autoimmunhämolytische Anämie
- ↑ Gupta S, Szerszen A, Nakhl F; et al. (2011). "Severe refractory autoimmune hemolytic anemia with both warm and cold autoantibodies that responded completely to a single cycle of rituximab: a case report". J Med Case Reports. 5: 156. doi:10.1186/1752-1947-5-156. PMC 3096571. PMID 21504611.
- ↑