GP1BA and Thrombocytopenia: We next compared the severity of thrombocytopenia between Ashwell–Morell-deficient (Aspgr2−/−) and syngeneic WT control mice and found thrombocytopenia in Aspgr2−/− mice was significantly attenuated when injected with the same concentration of anti-GPIbα mAb (Fig. 6e; Supplementary Fig. 7b), suggesting that the AMR indeed plays a significant role in the clearance of anti-GPIbα-bound platelets.