August 15, 2007 08:00 ET

SARS Study Reveals Potential Identification of Aggressive Cases

Measuring genes expressed during illness may be the key

Attention: Health/Medical Editor TORONTO, ONTARIO, NEWS RELEASE--(Marketwire - Aug. 15, 2007) - Researchers at University Health Network (UHN) have revealed that measuring the expression of certain genes during the early stages of illness may be able to predict a patient's risk of developing serious or even fatal complications for severe pneumonias with no known cure, such as Severe Acute Respiratory syndrome (SARS).

Their research paper entitled, "Interferon-Mediated Immunopathological Events Are Associated with Atypical Innate and Adaptive Immune Responses in Patients with Severe Acute Respiratory Syndrome," was published today in the Journal of Virology, one of the premier journals publishing original research concerning viruses.
Studying blood samples from 40 Toronto area SARS patients over the course of the 2003 outbreak, scientists were able to identify two unique interferon gene expression patterns produced by the immune system while reacting to the viral infection. Of the two patterns of interferons identified in the SARS patients who were followed throughout their illness, one pattern was present in patients who recovered quickly from SARS with mild to moderate effects on their health, and the other pattern was found in patients who either suffered a very critical and prolonged illness or who died as a result of contracting the SARS virus.
"This study suggests that information on how a SARS patient expresses these genes during their illness can be used to identify who may require more specific treatment," said Dr. Mark Cameron, a research scientist at UHN and the lead author of the study. "Also, we think that these patterns may apply to illnesses caused by flu viruses and that they should be considered in pandemic influenza preparedness, once we have done the work necessary."
In 2003, 40 per cent of people who contracted the SARS virus during the Toronto area outbreak developed what is considered a severe form of the disease and nearly a third of those patients died.
"This is an important study by a very large team of scientists, clinicians and front line health care workers," said Dr. David Kelvin, a senior scientist at UHN and study director, adding, "It may shed light on the underlying problems with the immune system in SARS patients."
During this study, researchers used a new device called a microarray, which can measure the expression of thousands of genes at the same time and can help to determine how a person's immune system is working during an illness following simple blood samples taken during the early stages of the disease.
Severe Acute Respiratory Syndrome (SARS) came to the world's attention in 2003. Most cases were in Asia, but the largest concentration of North American cases occurred in Toronto.
Support for this study came from grants from the Canadian Institutes for Health Research (CIHR), the National Institutes of Health (NIH) and Genome Canada, in partnership with Genome Quebec and the Ontario Genomics Institute.

About University Health Network (

University Health Network consists of Toronto General, Toronto Western and Princess Margaret Hospitals. The scope of research and complexity of cases at University Health Network has made it a national and international source for discovery, education and patient care. It has the largest hospital-based research program in Canada, with major research in cardiology, transplantation, neurosciences, oncology, surgical innovation, infectious diseases, and genomic medicine. University Health Network is a research and teaching hospital affiliated with the University of Toronto.

Contact Information

  • Nicole Bodnar, Public Affairs and Communications, University Health Network
    Primary Phone: 416-340-4636