Background: Acquired thrombotic thrombocytopenic purpura (TTP) is caused by development of antibodies against ADAMTS 13, a VWF multimer cleaving protease. Treatment involves urgent institution of plasma exchange. Rituximab, a monoclonal anti CD 20 antibody, has shown efficacy in the treatment of relapsed and refractory cases of TTP. It also decreases number of plasma exchanges required to attain remission. There is paucity of data regarding treatment and outcome of TTP from developing countries using rituximab in upfront therapy.

Aims: To evaluate treatment and outcome of acquired TTP in patients treated with plasma exchange and rituximab

Methods: Retrospective review of adult patients treated as acquired TTP in hematology department in Sir Ganga Ram Hospital New Delhi India from Jan 2016 to Dec 2019.

Results: A total of 8 patients were treated during above period (female 5 male 3), median age 50 years (32 – 57), mean Hb 7.4gm/dl (6.0-8.7), median platelet count 14 (10-26), schistocyte index 11.6% (4.3-21.8), serum LDH 1277 (411-2580). One patient had underlying HIV infection but was a treatment defaulter with very high viral load. ADAMTS 13 activity was less than 3 in all patients with mean inhibitor activity of 4.68 BU (1.6-12.1). Mean number of plasma exchanges needed were 8 (4-12). Two patients didn´t respond to plasma exchange and died after 5 days including one with HIV associated TTP. Six patients achieved complete remission and also received all 4 weekly courses of rituximab. None of the six patients have relapsed after a 28 months of median follow up (6-48 months).

Conclusions: Acute acquired TTP is frequently misdiagnosed as immune thrombocytopenic purpura resulting in delayed diagnosis resulting in significant early mortality. There is a need to diagnose TTP early and refer them to appropriate center for treatment with plasma exchange and rituximab for improving the outcome.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/treatment-of-acquired-thrombotic-thrombocytopenic-purpura-in-rituximab-era-a-single-center-experience-from-india/