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.

Recent Publications

  1. 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. 2017; :. doi: 10.1111/bjh.14985. PubMed PMID:29048127 .
  2. 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.
  3. 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 .
  4. Zufferey, A, Kapur, R, Semple, JW. Pathogenesis and Therapeutic Mechanisms in  Immune Thrombocytopenia (ITP). J Clin Med. 2017;6 (2):. doi: 10.3390/jcm6020016. PubMed PMID:28208757 PubMed Central PMC5332920.
  5. Kapur, R, Kim, M, Aslam, R, McVey, MJ, Tabuchi, A, Luo, A et al.. T regulatory cells and dendritic cells protect against transfusion-related acute lung injury via IL-10. Blood. 2017;129 (18):2557-2569. doi: 10.1182/blood-2016-12-758185. PubMed PMID:28202460 PubMed Central PMC5418638.
  6. Aslam, R, Burack, WR, Segel, GB, McVey, M, Spence, SA, Semple, JW et al.. Intravenous immunoglobulin treatment of spleen cells from patients with immune thrombocytopenia significantly increases the percentage of myeloid-derived suppressor cells. Br. J. Haematol. 2017; :. doi: 10.1111/bjh.14542. PubMed PMID:28165136 .
  7. Kapur, R, Semple, JW. Alleviation of gram-negative bacterial lung inflammation by targeting HECTD2. Ann Transl Med. 2016;4 (24):488. doi: 10.21037/atm.2016.11.41. PubMed PMID:28149850 PubMed Central PMC5233488.
  8. Kim, DY, Yu, J, Mui, RK, Niibori, R, Taufique, HB, Aslam, R et al.. The tyrosine kinase receptor Tyro3 enhances lifespan and neuropeptide Y (Npy) neuron survival in the mouse anorexia (anx) mutation. Dis Model Mech. 2017;10 (5):581-595. doi: 10.1242/dmm.027433. PubMed PMID:28093506 PubMed Central PMC5451163.
  9. Kapur, R, Aslam, R, Kim, M, Guo, L, Ni, H, Segel, GB et al.. Thymic-derived tolerizing dendritic cells are upregulated in the spleen upon treatment with intravenous immunoglobulin in a murine model of immune thrombocytopenia. Platelets. 2017;28 (5):521-524. doi: 10.1080/09537104.2016.1246718. PubMed PMID:27885866 .
  10. Kapur, R, Kim, M, Rondina, MT, Porcelijn, L, Semple, JW. Elevation of C-reactive protein levels in patients with transfusion-related acute lung injury. Oncotarget. 2016;7 (47):78048-78054. doi: 10.18632/oncotarget.12872. PubMed PMID:27793007 PubMed Central PMC5363642.
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Affiliations & Other Activities

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