Autoimmune Hemolytic Anemia

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Classification according to ICD-10
D59 Acquired hemolytic anemia
D59.0 Drug-induced autoimmune hemolytic anemia
D59.1 Other autoimmune hemolytic anemias
ICD-10 online (WHO version 2019)

An autoimmune hemolytic anemia (abbreviated AIHA ) is an acquired hemolytic anemia caused by autoantibodies , d. H. caused by antibodies directed against its own antigens . These antibodies attach to the erythrocytes (red blood cells) and under certain circumstances can lead to their destruction ( hemolysis ). Autoimmune hemolytic anemias are acquired, non-infectious diseases.

Terminology

The term 'autoimmune hemolytic anemia' describes a group of acquired diseases of the body's own defense system ( immune system ) in which there is a shortage of erythrocytes. Such an unphysiological deficiency is covered by the generic term “ anemia ”. Under the generic term 'autoimmune disease' ( old Gr. Αὐτός autós own, equal, self) are subsumed diseases that are associated with reactions of the body, in which a disturbed tolerance of the immune system to substances of the own body is based and that for the formation of Antibodies . 'Hemolysis' ( αἷμα haíma "blood" and λύσις lýsis "dissolution, dissolution, termination") in turn describes the dissolution of the red blood cells. In 1904 Julius Donath and Karl Landsteiner described an illness that they called 'paroxysmal cold hemoglobinuria' and which was due to the formation of antibodies against the body's own structures .

Classification

Hemolysis can be classified into:

  • extrinsic hemolysis, the cause of erythrocyte destruction lies outside the red blood cells (mostly acquired, including AIHA);
  • intrinsic hemolysis, due to a defect within the erythrocyte itself (mostly hereditary).

There are four different forms of AIHA:

  • AIHA of the heat type (incomplete antibodies (Ab) IgG), approx. 70%
  • AIHA of the cold type (also: cold agglutinin disease) (complete Ak IgM), approx. 20%
  • AIHA of the Donath-Landsteiner type or mixed or bithermal Ak (also: paroxysmal cold hemoglobinuria) approx. 10%
  • drug induced AIHA .

Depending on the "haemolytic effect" of the autoantibodies, a distinction is made between so-called complete antibodies , which can cause visible agglutination (clumping) of the erythrocytes, from incomplete antibodies , which do not. The former are usually of the immunoglobulin M (IgM) type, the latter of the immunoglobulin G (IgG) type. Autoantibodies on the erythrocyte surface can be detected with the direct Coombs test , autoantibodies in serum with the indirect Coombs test .

AIHA of the heat type

The heat-type AIHA is caused by autoantibodies that react optimally at body temperature, ie 37 ° C. Mostly they are antibodies of the IgG type (only rarely IgA or IgM). The incidence of heat-type AIHA is estimated to be about 1 in 50,000. It can occur at any age, but it occurs much more frequently in adulthood than in childhood. Women are more often affected than men. In about half of the cases, no external cause for the occurrence of the AIHA can be found, in the other half of the cases the AIHA of the heat type is typically associated with certain diseases:

The clinical appearance of the affected patients is extremely variable. It ranges from extensive wellbeing with only mild hemolysis to severe, possibly life-threatening symptoms with very pronounced hemolysis.

Cold agglutinin disease (cold-type AIHA)

The cold type AIHA is caused by so-called cold agglutinins , which are almost always of the IgM type. At temperatures lower than body temperature, these autoantibodies lead to cross-linking (agglutination) of the erythrocytes and then to hemolysis through complement activation . Causes of a cold-type AIHA can be:

A distinction is made between an acute and a chronic form. The acute form usually occurs in the wake of infections and usually disappears again after the infection has subsided. The chronic form occurs practically only in adulthood and is usually irreversible without therapy.

The hemolysis is pathophysiologically triggered by high-titer IgM cold autoantibodies. The affected erythrocytes are mainly destroyed intravascularly by the terminal complement components (C5b-9 or membrane attack complex ) and to a lesser extent phagocytosed by the C3b fixation . Clinically relevant IgG and IgA autoantibodies are extremely rare here.

Paroxysmal cold hemoglobinuria (AIHA of the Donath-Landsteiner type)

Paroxysmal (i.e., paroxysmal) cold hemoglobinuria is the most common AIHA in childhood. They are almost never found in adults. It usually occurs after a virus infection. It is usually caused by autoantibodies of the IgG type, more rarely IgM, which have a similar reaction pattern as the above. Have cold agglutinins. Acute hemolysis symptoms with hemoglobinuria and anemia after exposure to cold are typical . They often experience cramp-like abdominal pain, vomiting, diarrhea, fever or chills. Despite the severe clinical picture, the disease usually shows a benign course and the hemolysis usually resolves spontaneously within a few days.

Drug-induced immune hemolysis

The formation of autoantibodies can be induced by drugs. The drugs that most commonly can lead to AIHA are:

The mechanism of autoantibody formation is not fully understood.

Clinic and Symptoms

In addition to the typical symptoms of anemia (paleness, fatigue, poor performance, tachycardia , ringing in the ears, shortage of air during physical exertion), the symptoms of hemolysis show up: jaundice (yellow discoloration) of the skin and sclera due to bilirubin storage, dark urine (due to released hemoglobin and bilirubin Degradation products). The clinical course varies greatly. A very pronounced acute hemolysis is a severe clinical picture with fever, chills, abdominal pain, vomiting, nausea and can be acutely life-threatening. With massive hemolysis, kidney failure and shock can occur. In the case of drug-induced AIHA , hemolysis symptoms typically occur a few minutes to hours after the corresponding drug intake.

The blood count shows a decrease in the number of red blood cells and usually spherocytosis .

treatment

The anemia can be treated symptomatically with transfusions of packed red blood cells ("blood transfusions"). In the case of life-threatening symptoms of anemia, this must also be done without delay, even if the cross -match is positive. The treatment of the AIHA of the heat type initially includes the treatment of the underlying disease causing it, if one exists. The therapy is otherwise immunosuppressive (steroids, for example 1 mg / day kg body weight prednisolone ; if the effect is insufficient, add azathioprine ). Other therapies (administration of polyvalent immunoglobulins or rituximab or cyclophosphamide ) should only be used after the primary therapy has failed. In cold-type AIHA, avoidance of exposure to cold is important. The drug-induced AIHA is primarily treated by stopping the triggering drug.

literature

  • A. Salama, G. Gaedicke: Autoimmune Hemolytic Anemias. In: Pediatric Hematology. Springer, Heidelberg 2006, ISBN 3-540-03702-0 , pp. 147-154.
  • R. Eckstein: Immunohematology and transfusion medicine. Urban & Fischer / Elsevier, Jena / Munich 2004, ISBN 3-437-21032-7 .

Web links

  • Joachim Kunz: Autoimmune Hemolytic Anemia (AIHA). Competence Network Pediatric Oncology and Hematology, created on February 28, 2012, Editing: Ingrid Grüneberg, Approval: Gesche Tallen, Ursula Creutzig; last modified: March 1st, 2012 [1]
  • N. Madershahian, UFW Franke, J. Wippermann, H. Jütte, K. Liebing, J. Strauch, T. Wahlers: Cold agglutinins in cardiac surgery: literature review and consequences for operative management. KARDIOTECHNIK 3/2005, pp. 90–93 [2]

Individual evidence

  1. ↑ dimdi.de ( Memento of the original from July 12, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.dimdi.de