How is mechanism of action in IT?

➢ In persons with Immune Thrombocytopenia (ITP), platelets are coated with autoantibodies to platelet membrane antigens (usually IgG) with specificity for one or more platelet membrane glycoproteins. ➢ Immune destruction of immunoglobulin-coated platelets is mediated by macrophage, primarily but not exclusively in the spleen. ➢ The spleen is the key organ in the pathophysiology of ITP, not only because platelet autoantibodies are formed in the white pulp, but also because mononuclear macrophages in the red pulp destroy immunoglobulincoated platelets ➢ Despite the destruction of platelets by splenic macrophages, the spleen is normally not enlarged; Spleen size is normal in the absence of another underlying condition.