John W. Semple


Associate Scientist, Keenan Research Centre for Biomedical Science


Dr. John Semple obtained his PhD in Immunology from Queen’s University at Kingston and was a Diabetes Canada Fellow in the Banting and Best Department of Medical Research at the C.H. Best Institute, University of Toronto. He is a Professor in the Departments of Pharmacology, Medicine and Laboratory Medicine and Pathobiology at the University of Toronto and an Adjunct Scientist with Canadian Blood Services.

Dr. Semple’s research is aimed at understanding the cellular immune mechanisms responsible for the generation of IgG antibodies that recognize platelet antigens. These antibodies can lead to clinically significant adverse effects such as autoimmunity causing immune thrombocytopenia (ITP) and alloimmunity causing platelet transfusion refractoriness. In ITP, for example, his laboratory is interested in how platelet antigens are processed and presented by antigen-presenting cells to activate T lymphocytes. In platelet refractoriness, his group studies the pro-inflammatory nature of platelets responsible for adverse reactions during platelet transfusions, particularly how platelet Toll-like receptor expression modulates innate immune mechanisms. His laboratory also studies the recipient immune mechanisms that cause Transfusion Related Acute Lung Injury (TRALI), a serious complication of transfusion.

Professor Semple is the recipient of many awards and a member of several organisations, including the American and European Societies of Hematology, and has delivered over 120 presentations at international meetings. He has served as a reviewer for numerous journals and granting agencies and authored more than 150 papers in the area of platelet immunology.

Please note: Dr. Semple is not taking any summer students in 2018.

Recent Publications

  1. Semple, JW, Kapur, R. The Ultimate Murine Model of Immune Thrombocytopaenia. Thromb. Haemost. 2019; :. doi: 10.1055/s-0039-1678697. PubMed PMID:30727005 .
  2. Rebetz, J, Semple, JW, Kapur, R. The Pathogenic Involvement of Neutrophils in Acute Respiratory Distress Syndrome and Transfusion-Related Acute Lung Injury. Transfus Med Hemother. 2018;45 (5):290-298. doi: 10.1159/000492950. PubMed PMID:30498407 PubMed Central PMC6257140.
  3. Semple, JW, Kapur, R. Moving target PF4 directs HIT responses. Blood. 2018;132 (7):678-679. doi: 10.1182/blood-2018-07-859975. PubMed PMID:30115634 .
  4. Kapur, R, Kim, M, Rebetz, J, Hallström, B, Björkman, JT, Takabe-French, A et al.. Gastrointestinal microbiota contributes to the development of murine transfusion-related acute lung injury. Blood Adv. 2018;2 (13):1651-1663. doi: 10.1182/bloodadvances.2018018903. PubMed PMID:29991496 PubMed Central PMC6039664.
  5. Guo, L, Kapur, R, Aslam, R, Hunt, K, Hou, Y, Zufferey, A et al.. Antiplatelet antibody-induced thrombocytopenia does not correlate with megakaryocyte abnormalities in murine immune thrombocytopenia. Scand. J. Immunol. 2018;88 (1):e12678. doi: 10.1111/sji.12678. PubMed PMID:29855061 .
  6. Semple, JW, McVey, MJ, Kim, M, Rebetz, J, Kuebler, WM, Kapur, R et al.. Targeting Transfusion-Related Acute Lung Injury: The Journey From Basic Science to Novel Therapies. Crit. Care Med. 2018;46 (5):e452-e458. doi: 10.1097/CCM.0000000000002989. PubMed PMID:29384784 .
  7. Zufferey, A, Speck, ER, Machlus, KR, Aslam, R, Guo, L, McVey, MJ et al.. Mature murine megakaryocytes present antigen-MHC class I molecules to T cells and transfer them to platelets. Blood Adv. 2017;1 (20):1773-1785. doi: 10.1182/bloodadvances.2017007021. PubMed PMID:29296823 PubMed Central PMC5728336.
  8. Kapur, R, Catalina, MD, Aslam, R, Speck, ER, Francovitch, RF, Semple, JW et al.. A highly purified form of staphylococcal protein A alleviates murine immune thrombocytopenia (ITP). Br. J. Haematol. 2018;183 (3):501-503. doi: 10.1111/bjh.14985. PubMed PMID:29048127 .
  9. Kapur, R, Kim, M, Rebetz, J, Rondina, MT, Porcelijn, L, Semple, JW et al.. Low levels of interleukin-10 in patients with transfusion-related acute lung injury. Ann Transl Med. 2017;5 (16):339. doi: 10.21037/atm.2017.04.37. PubMed PMID:28861436 PubMed Central PMC5566739.
  10. McVey, MJ, Kim, M, Tabuchi, A, Srbely, V, Japtok, L, Arenz, C et al.. Acid sphingomyelinase mediates murine acute lung injury following transfusion of aged platelets. Am. J. Physiol. Lung Cell Mol. Physiol. 2017;312 (5):L625-L637. doi: 10.1152/ajplung.00317.2016. PubMed PMID:28283474 .
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Affiliations & Other Activities

  • Professor, Pharmacology, Medicine and Laboratory Medicine and Pathobiology, University of Toronto
  • Adjunct Scientist, Canadian Blood Services