Understanding Why Some H1N1 Infections Lead to Severe Illness or Death

Author: University Health Network
Published: 2009/12/15 - Updated: 2025/01/16
Publication Details: Peer-Reviewed, Informative
Category Topic: H1N1 Virus (Swine Flu) - Academic Publications

Page Content: Synopsis - Introduction - Main - Insights, Updates

Synopsis: This paper offers valuable insight into why some H1N1 patients develop severe pneumonia, focusing on the role of interleukin 17 (IL-17) in exacerbating the immune response. It presents groundbreaking research by Canadian and Spanish scientists, which could potentially lead to early diagnostic tests and targeted treatments for high-risk patients. The findings hold promise for improving treatment strategies for severe flu cases, ultimately advancing the understanding of H1N1-related complications - Disabled World (DW).

Introduction

An international team of Canadian and Spanish scientists have found the first potential immunological clue of why some people develop severe pneumonia when infected by the pandemic H1N1 virus.

Main Content

The study analyzed different levels of regulating molecules for 20 hospitalized patients, 15 outpatients and 15 control subjects in 10 Spanish hospitals during the first pandemic wave in July and August 2009.

Researchers from the Hospital Clinico Universitario de Valladolid in Spain and the University Health Network found high levels of a molecule called interleukin 17 in the blood of severe H1N1 patients, and low levels in patients with the mild form of the disease.

Interleukin 17 is produced by the body and is important in the normal regulation of white blood cells which fight infection and disease. In certain circumstances, the molecule becomes "out of control", leading to inflammation and autoimmune diseases. The research paper titled, "Th1 and Th17 hypercytokinemia as early host response signature in severe pandemic influenza" is published in the December issue of the Journal of Critical Care.

"In rare cases, the virus causes lung infections requiring patients to be treated in hospital. By targeting or blocking TH17 in the future, we could potentially reduce the amount of inflammation in the lungs and speed up recovery," says Dr. David Kelvin, the leader of the Canadian team, Head of the Experimental Therapeutics Division, Toronto General Hospital Research Institute, University Health Network and Professor of Immunology, University of Toronto. Dr. Kelvin added that the clinical applications of this work is still many years away.

Dr. Kelvin did note, however, that a test to determine who has high levels of the molecule is possible in the near future.

"A diagnostic test could let us know early who is at risk for the severe form of this illness quickly," he said, adding that high levels would indicate a failure of the immune system to eliminate the virus, similar to what happened during the 1918 Spanish flu when huge numbers of deaths occurred due to a deadly influenza A virus strain of subtype H1N1.

Dr. Jesus Bermejo-Martin, the coordinator of the Spanish team, thinks that identifying drugs able to regulate the activity of IL-17 may provide alternative treatments for patients with severe H1N1.

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, infectious diseases, neurosciences, oncology, surgical innovation, and genomic medicine. The Toronto General Research Institute has more than 350 scientists, students and support staff, more than $65 million in external funding, and its staff is published in more than 600 publications a year. University Health Network is a research and teaching hospital affiliated with the University of Toronto.

Insights, Analysis, and Developments

The above article sheds light on the complex immune response triggered by the H1N1 virus, specifically how elevated interleukin 17 levels can lead to severe illness in some individuals. By revealing potential biomarkers and insights into treatment, it underscores the importance of ongoing research to better understand the underlying mechanisms of flu-related complications. This work provides a promising step toward more effective prevention and personalized care for those at higher risk, highlighting the critical need for continued medical investigation

Attribution/Source(s): This peer reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by University Health Network and published on 2009/12/15, this content may have been edited for style, clarity, or brevity.