Current and emerging treatments based on novel mechanisms for immune thrombocytopenia

Immune thrombocytopenia(ITP)is an autoimmune bleeding disorder characterized by increased platelet destruction and impaired platelet production.The pathophysiology of ITP is complicated and incompletely understood.It is traditionally recognized that antibody-coated platelets are prematurely cleared via Fc-independent or dependent mechanism in the spleen,liver,or both.Antibody-mediated complement activation and desialylation can also destroy platelets.In addition,antibodies can inhibit megakaryocyte production and maturation.Abnormalities in cellular immunity have also been described,including skewing of T helper(Th)cells toward a type 1 T helper(Th1)and type 17 T helper(Th17)phenotype,reduction of regulatory T-cell activity,and an increase in cytotoxic T cells.