Professional background

Dr Mari Thomas is a haematology consultant in the thrombosis team at UCLH. She undertook her PhD at UCL looking into the role of antibodies in TTP. As part of the TTP team, she manages both inpatients and outpatients with TTP and other thrombotic microangiopathies, such as atypical HUS.

Her other areas of interest include venous thromboembolism in cancer patients and obstetric haematology. Dr Thomas leads the cancer VTE service at UCLH. She also leads the obstetric haematology service, running a joint antenatal clinic for high-risk pregnancies with obstetric colleagues.

Research interests

TTP, cancer thrombosis, obstetric haematology


Woolley P, Newton R, Mc Guckin S, Thomas M, Westwood JP, Scully MA Immune thrombocytopenia in adults; a single centre review of demographics, clinical features and treatment outcomes. E J Haem DOI: 10.1111/ejh.13456

Sayar Z, Weatherill A, Keddie S, Sive J, Lunn M, Thomas M, D’Sa S. High Rates of Venous and Arterial Thrombotic Events in Patients With POEMS Syndrome: Results From the UCLH (UK) POEMS Registry Blood Adv 2020 May 26;4(10):2139-2142.

Thomas MR, Scully M. Microangiopathy in Cancer: Causes, Consequences, and Management. Cancer Treat Res. 2019;179:151-158

Vendramin C, Thomas M, Westwood JP, Scully M Bethesda Assay for Detecting Inhibitory Anti-ADAMTS13 Antibodies in Immune-Mediated Thrombotic Thrombocytopenic Purpura. TH Open. 2018 Sep 26;2(3):e329-e333.

Stubbs MJ, Low R, McGuckin S, Newton R1, Thomas M, Westwood JP, Shah R, Cheesman S, Scully MA Comparison of Rituximab originator (MabThera) to biosimilar (Truxima) in patients with immune-mediated thrombotic thrombocytopenic purpura. Br J Haematol. 2019 Jun;185(5):912-917

Alwan F, Vendramin C, Liesner R, Clark A, Lester W, Dutt T, Thomas W, Gooding R, Biss T, Watson HG, Cooper N, Rayment R, Cranfield T, van Veen JJ, Hill QA, Davis S, Motwani J, Bhatnagar N, Priddee N, David M, Crowley MP, Alamelu J, Lyall H, Westwood JP, Thomas M, Scully M. Characterization and treatment of congenital thrombotic thrombocytopenic purpura. Blood. 2019 Apr 11;133(15):1644-1651

Austin K, George J, Robinson EJ, Scully M, Thomas MR. Retrospective cohort study of venous thromboembolism rates in ambulatory cancer patients, association with Khorana score and other risk factors. J Hematol. 2019;8(1):17-25

Vendramin C, Thomas M, Westwood JP, McGuckin S, Scully M. Rituximab-induced acute and delayed serum sickness in thrombotic thrombocytopenic purpura: the role of anti-rituximab antibodies. Br J Haematol. 2019 Mar;184(5):858-861

Mulder FI, Candeloro M, Kamphuisen PW, Di Nisio M, Bossuyt PM, Guman N, Smit K, Büller HR, van Es N; CAT prediction collaborators. The Khorana score for prediction of venous thromboembolism in cancer patients: a systematic review and meta-analysis. Haematologica. 2019 Jan 3. pii: haematol.2018.209114.

Thomas MR, Bullock T, Kendall GS, Win N. Use of thawed and washed red cells preserved in extended storage media for neonatal exchange transfusion. Transfus Med. 2019 Jan doi: 10.1111/tme.12574.

Stubbs MJ, Thomas M, Vendramin C, Sonesson E, Kjellman C, Järnum S, Stenberg Y, Elfving C, Scully M. Administration of immunoglobulin G-degrading enzyme of Streptococcus pyogenes (IdeS) for persistent anti-ADAMTS13 antibodies in patients with thrombotic thrombocytopenic purpura in clinical remission. Br J Haematol. 2018 Nov doi: 10.1111/bjh.15706

Stubbs M, Mouyis M, Thomas M. Clinical Update in DVT. British Medical Journal. 2018 Feb 22;360:k35

Alwan F, Vendramin C, Vanhoorelbeke K, Langley K, McDonald V, Austin S, Clark A, Lester W, Gooding R, Biss T, Dutt T, Cooper N, Chapman O, Cranfield T, Douglas K, Watson HG, van Veen JJ, Sibson K, Thomas W, Manson L, Hill QA, Benjamin S, Ellis D, Westwood JP, Thomas M, Scully M. Presenting ADAMTS13 antibody and antigen levels predict prognosis in immune-mediated thrombotic thrombocytopenic purpura. Blood. 2017 Jul 27;130(4):466-471

Westwood JP, Thomas M, Alwan F, McDonald V, Benjamin S, Lester WA, Lowe GC, Dutt T, Hill QA, Scully M. Rituximab prophylaxis to prevent thrombotic thrombocytopenic purpura relapse: outcome and evaluation of dosing regimens. Blood Adv. 2017 Jun 26;1(15):1159-1166

Vendramin C, McGuckin S, Alwan F, Westwood JP, Thomas M, Scully M. A single-center prospective study on the safety of plasma exchange procedures using a double-viral-inactivated and prion-reduced solvent/detergent fresh-frozen plasma as the replacement fluid in the treatment of thrombotic microangiopathy. Transfusion. 2016 doi: 10.1111/trf.13877

Pavenski K, Cataland S, Kremer Hovinga J, Thomas M, Vanhoorelbeke K. Thrombotic Thrombocytopenic Pupura (TTP) Symposium Proceedings. Expert Rev Hematol. 2016 9(8):733-5.

Thomas MR, Robinson S, Scully MA. How we manage thrombotic microangiopathies in pregnancy. Br J Haematol. 2016 Jun;173(6):821-30.

Patriquin CJ, Thomas MR, Dutt T, McGuckin S, Blombery PA, Cranfield T, Westwood JP, Scully M. Bortezomib in the treatment of refractory thrombotic thrombocytopenic purpura.Br J Haematol. 2016 Jun;173(5):779-85.

Thomas MR, de Groot R, Scully MA, Crawley JTB. Pathogenicity of anti-ADAMTS13 antibodies in acquired thrombotic thrombocytopenic purpura. EBioMed 2015

South K, Luken BM, Crawley JT, Phillips R, Thomas M, Collins RF, Deforche L, Vanhoorelbeke K, Lane DA. Conformational activation of ADAMTS13. Proc Natl Acad Sci 2014;111(52):18578-83.

Scully M, Thomas M, Underwood M, Watson H, Langley K, Camilleri RS et al . Thrombotic thrombocytopenic purpura and pregnancy: presentation, management, and subsequent pregnancy outcomes. Blood 2014;124(2):211-9

Thomas M, Scully M. (2014) Thrombotic Microangiopathies. In: Haematology in Critical Care (pp. 62-8) Oxford, UK, Wiley.

Camilleri RS, Scully M, Thomas M, Mackie IJ, Liesner R, Chen WJ, Manns K, Machin SJ. A phenotype-genotype correlation of ADAMTS13 mutations in congenital thrombotic thrombocytopenic purpura patients treated in the United Kingdom. J Thromb Haemost 2012; 10(9):1792-801

Thomas MR, McDonald V, Machin SJ, Scully MA. Thrombotic thrombocytopenic purpura associated with statin therapy. Blood Coagul Fibrinolysis 2011; 22(8):762-3

Thomas MR, Machin SJ, Mackie I, Scully MA. B cell activating factor is elevated in acute idiopathic thrombotic thrombocytopenic purpura. Br J Haematol 2011; 155(5):620-2