Since the presence of anti-ADAMTS13 inhibitor at presentation has been reported to be associated with increased likelihood of TTP relapse (45, 46), then it is not surprising that increased AMC at admission might reflect the expansion of MDSCs in TTP patients during acute episodes, which in turn associates with suppression of B cell responses, a decrease of anti-ADAMTS13 antibody production, an increase in ADAMTS13 activity and an improvement in RFS. This evidence concerns the gene ADAMTS13 and thrombotic thrombocytopenic purpura.