Harry Janssen, PhD, MD

Affiliate Scientist, Toronto General Hospital Research Institute (TGHRI)

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Keywords: hepatitis B, hepatitis C, antivirals, primary sclerosing cholangitis, primary biliary cirrhosis, autoimmune hepatitis, portal vein thrombosis, Budd-Chiari syndrome, interferon

Harry L.A. Janssen is Professor of Medicine at the University of Toronto, Ontario, Canada, where he holds the Francis Family Chair in Hepatology. He currently works at Toronto General Hospital as Chief of Hepatology and Director of the Toronto Centre for Liver Disease.

Dr. Janssen graduated from medical school in Nijmegen, The Netherlands. During his study he spent one year as research fellow in Hepatology at the Mayo Clinic. He obtained his PhD in Rotterdam on the role of immune modulating therapy in chronic hepatitis B. Following his training in Internal Medicine in Leiden and Gastroenterology at the Erasmus University in Rotterdam, he returned to the Mayo Clinic for a Research Fellowship in Hepatology at the Center of Basic Research in Digestive Diseases. In 2001 he became a faculty member and in 2006 he was appointed as full Professor of Hepatology at the Erasmus University and Chief of the Section Liver Diseases and Transplantation at the Erasmus Medical Center in Rotterdam. After a successful career in Rotterdam he moved in 2013 to Canada to head the Liver Program at Toronto Western Hospital. In 2016 he merged all three Toronto Liver Programs into the Toronto Centre for Liver Disease to become the biggest liver program in North America, based at Toronto General Hospital, University Health Network.

Dr. Janssen has coordinated numerous global multicenter studies on the natural history and treatment for chronic viral hepatitis and other liver diseases. His clinical and translational research aiming for immunological control and cure of hepatitis B and C have led to several globally used novel treatment concepts. Based on publications and citations he is currently ranked as the nr.1 global expert in chronic hepatitis B (Expertscape, Sept. 2020). His research contributions include sustained federal funding (greater than 20 years), over 500 peer reviewed publications, an H-index of more than 100, and over 45,000 citations (Google Scholar). He has acquired over $50 million USD in research funding from many different organizations such as NIH, European Commission, CIHR, NWO and ZonMW. He has received several prestigious international awards and has mentored over 50 PhD students, many of whom have taken leadership positions in the field of Hepatology or Virology. In addition to his longstanding expertise in antiviral therapy of chronic viral hepatitis, he is a leading scientist in the field of vascular disorders of the liver. Dr. Janssen is a member of the EASL Guideline Committees for both Hepatitis B and for Vascular Liver Disease. He currently serves as the Head of the Division of Experimental Therapeutics at the Toronto General Hospital Research Institute (TGHRI), Vice Chair of the AASLD Special Interest Group (SIG) for Hepatitis B and the Global Chair of the International Symposium on Viral Hepatitis and Liver Disease (ISVHLD).
Dr. Janssen has coordinated two lines of research over the last several years.
  • Strategies to identify immune control and disease remission in chronic viral hepatitis
    In this research area, Dr. Janssen investigates which virus and host-related conditions are required for immunological control of viral hepatitis B (HBV) and C (HCV), and in parallel, for sustained response to antiviral therapy. Large-scale multicentre clinical HBV and HCV intervention studies were combined with ancillary fundamental studies using an intensive translational approach. Clinical studies on the natural history and outcome of medical interventions of chronic viral hepatitis were mostly investigator-initiated. In 2001 Dr. Janssen was awarded a ZonMW Clinical Fellowship, in 2004 a ZonMW VIDI grant, and in 2008 European grant (VIRGIL, 6th framework) to unravel the immunological mechanism of disease chronicity and response to antiviral therapy in viral hepatitis B and C. Currently he is the Principal Investigator of the Hepatitis B Research Network (HBRN) funded by the National Institutes of Health (NIH).
  • Hypercoagulability and liver disease
    During his time at the University of Leiden (1998), Dr. Janssen studied on a national level the etiology of thrombosis of the hepatic vasculature. This was a starting point for European large-scale patient-based cohort studies to elucidate the multifactorial aetiology, the prognostic factors and the efficacy of the various treatment modalities for these life-threatening disorders. In 2001, Dr. Janssen founded the European Network for Vascular Disorders of the Liver (En-Vie), a consortium of expert centres from 9 European countries. He received a grant from the European Community (5th framework) to set up national networks, an on-line common database to federate tissue sample banks.

    Activities for these research lines resulted in an extensive scientific network, numerous high impact papers and abstracts that were presented at scientific meetings of the American Association for the Study of Liver Diseases during the past five years (2008-2012).
  • Future research
    Dr. Janssen's track record in research on the immune reactivity and long-term outcome of chronic viral hepatitis is a strong basis for future clinical and translational research at the University Health Network (UHN), which hosts the largest liver clinic in North America (Toronto Western Hospital & Toronto General Hospital).

    Dr. Janssen is enhancing UHN's Liver Disease Research Program by establishing his own clinical trial and clinical translational research programs, and obtaining financial support for these endeavors from peer review granting agencies and/or industrial partners. More concretely, he intends to initiate coordination of large scale investigator-initiated clinical research on viral hepatitis, autoimmune liver disease and liver cancer. With the number of liver patients in the Greater Toronto Area and, with the large knowledge and infrastructure for hepatology available at UHN, Dr. Janssen hopes this goal can be achieved within 3 years. He also intends to further unravel at a mechanistic level, the relationship between immune reactivity and the disease progression of various liver diseases, by founding a Liver Lab with combined laboratory space and shared common equipment and facilities for fundamental and translational liver research.

For a list of Dr. Janssen's publications, please visit PubMed or Scopus.
Affiliate Scientist, Toronto General Hospital Research Institute (TGHRI)

Professor, Department of Medicine, University of Toronto
Head, University Health Network Liver Clinic