It is of interest to note, although the findings of a normal ADAMTS-13 does not support the diagnosis of TTP, rare cases have been reported of MCTD complicated by TTP with normal ADAMTS-13 levels.8 Whereas plasma exchange is contraindicated with pure SRC, due to the possibility of a bradykinin mediated reaction resulting in severe hypotension, which is treated with the initiation of ACEi and strict blood pressure control. This evidence concerns the gene ADAMTS13 and thrombotic thrombocytopenic purpura.