A 24-year-old woman with newly diagnosed warm autoimmune hemolytic anemia has IgG autoantibodies coating her red blood cells. In which organ are these antibody-coated erythrocytes primarily destroyed?

• A Liver via Kupffer cells recognizing C3b opsonization
• B Spleen via macrophage Fc gamma receptor recognition ✓
• C Bone marrow via NK cell ADCC
• D Lungs via alveolar macrophage phagocytosis

Explanation

Warm AIHA involves IgG-coated RBCs that are recognized by Fc gamma receptors on splenic macrophages, leading to partial phagocytosis and formation of spherocytes. The spleen is the primary site of extravascular hemolysis in warm AIHA. The liver is more important in cold agglutinin disease (IgM-mediated, C3b opsonization). ADCC by NK cells is not the primary mechanism. Pulmonary macrophages do not play a significant role.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.