New Study of Toronto SARS Patients Reveals Potential for Future Identification of Aggressive Cases

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 patients 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, 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.

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 percent 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 healthcare 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 persons immune system is working during an illness following simple blood samples taken during the early stages of the disease.

SARS came to the worlds 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.

Source: University Health Network