Warm Autoimmune Hemolytic Anemia

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Warm Autoimmune Hemolytic Anemia

• Lisa Rose-Jones, MD
• Monday, Aug 24th

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Autoimmune Hemolytic Anemia Warm Agglutinins

• Due to IgG antibodies that react with protein
  antigens on RBC surface _at_ body temperature
• Extravascular (red blood cells are destroyed in
  the spleen and other reticuloendothelial organs)
  hemolysis

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HemolysisDiagnosis

• Typically find Hgb in range of 7-10 g/dL (Hct
  21-30)
• Hemolysis Increased Reticulocyte/LDH/Indirect
  Bilirubin Decreased Haptoglobin
• Some w/ acute hemolysis may have
  reticulocytopenia from lag in marrow
  responsiveness 2/2 hemolytic stress

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Warm Hemolysis Dxcontd

• Peripheral smear show spherocytosis (appear
  abnormally small and will lack the central
  pallor)

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Direct Coombs test

• Test for dignosis of warm AIHA
• Adherent proteins are washed free from pts RBCs,
  mixed w/ antiserum or monocolonal Abs against
  different Immunoglobulins (IgG, C3d) if
  present on RBC surface degree agglutination
  quantitated by ELISA

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Differential Diagnosis

• Drug Induced
• Cephalosporins, PCN derivatives, NSAIDs,
  Quinidine
• Cold Agglutinins, (cold reacting IgM
  antibodies). Acral cynaosis

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Pathogenesis of RBC destruction in AIHA

• Immunoadherence RBC (target cell) affixed to
  destructive cell (phagocyte) through
  immunoprotein molecule on each cell
• ingestion may be partial, resulting in RBC w/
  reduced surfacevol ratio spherocyte, b/c
  reduced deformability many cant cross splenic
  sinuses slitsdestroyed

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Why Autoantibody Production?

• B cell clones appear to be altered to produce
  these antibodies at high pathogenic titers
• Exacerbated by immune reaction of microbial
  infection?, viral infections (HIV, Mono)
• Rxn to blood transfusion or transplant my
  initiate this process

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Why?.......

• Higher incidence of autoantibodies associated w/
  Systemic Lupus
• 11 of patients w/ Chronic Lymphocytic Leukemia
  (CLL), likely b/c of again abnormal B cells
  (neoplastic proliferation)

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Treatment Goals

• Reduce the amount of Antibody being produced
  reduce its effiency in destroying RBCs
• Success ? Cure, typically still evidence of
  persistent activity of underlying process.
  Control degree of anemia

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Reduce Antibody Response

1. Corticosteroids (1mg/kg Prednisone), see response
   in 1-3 wks
2. Cytotoxic Agents Azathioprine
   Cyclophosphamide, given if lack
   response/inability tolerate 1. Response seen 1
   month. Case reports in resistant cases use of
   Cyclosporine, Mycophenolate, and anti-CD20
   antibodies (Rituximab)

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Reduce Antibody Effectiveness

• Splenectomy (removing primary site of
  destruction)
• IVIG only occ effective (40) in tx of AIHA
  refractory to conventional therapy w/ Prednisone
  splenectomy (reducing the interaction b/w
  spleen macrophages Ab coated RBCs)

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RBC Transfusions

• Tested for alloantibodies (develops following
  pregnancy or prior transfusions) autoantibodies
• Experience has indicated most pts will tolerate
  serologically incomplatible (atuoantibodies)
  blood

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THE END!!