ADAMTS13 and thrombotic thrombocytopenic purpura: ADAMTS13 levels were available in 32/105 patients, while only 13/32 of these patients had severe ADAMTS13 deficiency, indicating that in most of previous studies, the diagnosis of SLE-TTP was not based on ADAMTS13 levels, and that a substantial proportion of lupus patients with TMA may be diagnosed with TTP despite non-severe ADAMTS13 deficiency [9].