Autoimmunhämolytische Anämien stellen eine Untergruppe der hämolytischen Anämien dar.
Auch wenn es sich um seltene Erkrankungen handelt, ist eine zügige Diagnosestellung
wichtig, um betroffene Patienten schnell in spezialisierte hämatologische Zentren
und Praxen vorzustellen. Dieser Beitrag soll einen kurzen Überblick über die verschiedenen
Unterformen, die Diagnostik sowie Therapieansätze geben.
Abstract
Autoimmune haemolytic anemia (AIHA) is defined as the immune-mediated destruction
of red blood cells. In most cases, antibodies that target surface antigens on erythrocytes
lead to their premature degradation in the spleen or, less commonly, in the liver.
The term includes a heterogenous group of diseases, which differ largely in pathophysiology
and treatment. The two most common entities are warm AIHA and cold AIHA. Diagnostic
testing involves the analysis of haemolytic markers like lactate dehydrogenase, haptoglobin
and unconjugated bilirubin as well as a hemoglobin and reticulocytes. In case of a
haemolytic anemia, further testing like a blood smear and a direct antiglobulin test
should follow. As diagnostic testing and treatment of AIHA are complex, affected patients
should always be referred to a hematologist.
In warm AIHA, mainly IgG autoantibodies bind to their antigen on the erythrocyte surface
at body temperature, leading to their premature destruction in the spleen. First line
treatment options include the administration of steroids which mitigate the destruction
of red blood cells by macrophages in the spleen. In contrast, IgM autoantibodies in
cold AIHA lead to intravasal agglutination of erythrocytes and complement activation.
The IgM antibodies have their highest affinity below body temperature which is why
patients experience symptoms mainly in cold-exposed body areas. Although the IgM antibodies
dissolve at body temperature, the complement-loaded erythrocytes are destroyed in
the liver. Therapeutic options include protection from cold and immunosuppressive
agents or complement inhibition.
Schlüsselwörter
Autoimmunhämolytische Anämie - Coombs-Test - wAIHA - cAIHA - Kälteagglutin-Krankheit
Key words
autoimmune haemolytic anemia - Coombs test - warm AIHA - cold AIHA - cold agglutinin
disease
