Anti-RBC Antibody Mediated Erythrocyte Phagocytosis and its Therapeutic Role in Immune Thrombocytopenia (ITP)

Immune thrombocytopenia (ITP) is a platelet autoimmune disorder diagnosed by an isolated low platelet count and the absence of other causes of thrombocytopenia. Rh immune globulin (anti-D) is a first line therapy for ITP which targets the RhD antigen on erythrocytes. Monoclonal antibodies are desirable alternatives to anti-D for various reasons. Here, nine erythrocyte-specific antibodies were evaluated for their ability to opsonize RBCs for phagocytosis and prevent platelet destruction in vitro using these opsonized RBCs. Only three (34-3C, TER119 and M1/69) effectively induced phagocytosis of RBCs. Antibodies that were able to opsonize RBCs for phagocytosis also inhibited platelet phagocytosis. TER119, 34-3C and M1/69 are the only antibodies tested that ameliorate ITP in a passive mouse model. These data suggest that the ability of an antibody to prevent platelet phagocytosis in vitro could be indicative of its ability to ameliorate ITP. We speculate that a future screening tool to test the therapeutic ability of monoclonal antibodies in ITP may be possible using these methods.M.Sc.2018-03-15 00:00:0