Thrombotic Microangiopathic Hemolytic Anemia With Reduction of ADAMTS13 Activity: Initial Manifestation of Childhood-Onset Systemic Lupus Erythematosus

Severe manifestations of systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), and thrombotic thrombocytopenic purpura (TTP) are characterized by multiorgan thrombotic microangiopathy. We describe reduction of ADAMTS13 activity and the development of systemic autoimmunity in all 8 children initially diagnosed with acquired noncongenital TTP during an 8.5-year period. Median age at diagnosis was 12.0 years (range, 2.6-17.3 years). ADAMTS13 activity was absent (