TTP/HUS: observational studies generate hypotheses that lead to randomized controlled trials

Thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS) is a disease syndrome, and its history exemplifies how small observational studies lead to hypotheses that spawn randomized control trials (RCTs). Moschowitz's original case report coupled with the case findings of Bukowski and Byrne led to the RCT of Rock and the Canadian Apheresis Group that proved plasma exchange was superior to plasma infusion for the treatment of …