en - Adults Hematology & Oncology Adults Hematology & Oncology پژوهشي Original Article Background: Rituximab can induce a durable remission in plasma exchange refractory thrombotic thrombocytopenic purpura (TTP). Timing of Rituximab infusion in combination with plasma exchange (PE) and long term follow-up for probable side effects of such treatment is still lacking.<br> Methods: This study was conducted among 10 patients with plasma exchange refractory TTP. According to the study designation, first PE was performed within 36-48 hours after first dose of rituximab.<br> Results: Eight of ten (80%) patients received 1 course of rituximab. Two of ten (20%) patients received another course of rituximab due to relapse. Repsonse rate (RR) to rituximab in combination with plasma exchange, was 90%. Overall Survival of the patients was 90% and 1 and 5-year relapse free survival rate (RFS) was 90% and 83%, respectively. One of the patients expired due to Systemic Lupus Erythematosus flare up.<br> Conclusion: According to this study, treatment of refractory TTP with rituximab in combination with PE could be effective.<br> Iranian Registry of Clinical Trials: IRCT2017012232125N1 Rituximab, Thrombotic thrombocytopenic purpura, Plasma exchange, Refractory 87 91 http://ijbc.ir/browse.php?a_code=A-10-368-1&slc_lang=en&sid=1 Alireza Sadeghi Sadeghi_hem@yahoo.com 10031947532846004341 10031947532846004341 No Assistant Professor, Department of Hematology-Oncology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Farzaneh Ashrafi f_ashrafi@med.mui.ac.ir 10031947532846004342 10031947532846004342 No Assistant Professor, Department of Hematology-Oncology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Arman Sourani armansourani@yahoo.com 10031947532846004343 10031947532846004343 Yes Student Research Committee, School of medicine, Isfahan University of Medical sciences, Isfahan, Iran