Autoimmune Hemolytic Anemia

Chapter 16 Autoimmune Hemolytic Anemia



Ulrich Jäger, Klaus Lechner



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Figure 16-1 MECHANISM OF EXTRAVASCULAR HEMOLYSIS IN AUTOIMMUNE HEMOLYTIC ANEMIA.


A, Macrophage encounters an IgG-coated erythrocyte and binds to it via its Fc receptors. Thus entrapped, the red blood cell (RBC) loses bits of its membrane as a result of digestion by the macrophage’s ectoenzymes. The discoid erythrocyte transforms into a sphere. B, RBC lightly coated with IgG (and therefore incapable of activating the complement cascade) is preferentially removed in the sluggish circulation of the spleen. C, RBC with a heavy coat of IgG; thus, C3b (black circles) can be removed both by the spleen and the liver.


(From Cunnigham MJ, Silberstein LE: Autoimmune Hemolytic Anemia. In Hoffman R, Benz EJ Jr, Shattil SJ, et al, eds: Hematology: Basic principles and practice, ed 4, 2005, Philadelphia, Elsevier.)



Table 16-1 Properties and Specificities of Red Blood Cell Autoantibodies

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CAIHA, Cold autoimmune hemolytic anemia; Ig, immunoglobulin; WAIHA, warm autoimmune hemolytic anemia.



Four Important Questions for the Diagnosis and Management of Autoimmune Hemolytic Anemia


It is of utmost importance to differentiate between various types of AIHA. A stepwise approach helps in making the right decisions:



Question 1: Hemolytic anemia? The basic features of hemolytic anemia are reticulocytosis, low haptoglobin levels, elevated indirect bilirubin, and elevated LDH.


Question 2: Autoimmune hemolytic anemia? A direct DAT is initially performed with a polyspecific antibody to detect IgG or complement C3d bound to RBCs. If the DAT result is positive, the diagnosis of AIHA is established.


Question 3: Warm or Cold Autoimmune Hemolytic Anemia?

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Jun 12, 2016 | Posted by in HEMATOLOGY | Comments Off on Autoimmune Hemolytic Anemia
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