Cytokine levels may predict poor outcome in influenza patients
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A newly identified signature immune response could help doctors identify which newly diagnosed influenza patients are more likely to develop severe symptoms and suffer poor outcomes, according to recent study findings published in the American Journal of Respiratory and Critical Care Medicine.
“Patients in this study could handle the flu virus and clear it from their lungs in a week to 10 days,” Paul Thomas, PhD, an assistant member of the St. Jude Department of Immunology said in a press release. “The problem for patients with this immune signature is likely the inflammatory environment in their airways created by the innate immune system in response to the virus. Clinically, we need to explore targets therapies to address this problem separately from efforts to clear the virus.”
Thomas and colleagues evaluated 84 people aged 3 weeks to 71 years, including 41 infants and toddlers aged 23 months or younger, with community-acquired influenza during the 2009-2010 and 2010-2011 influenza seasons to determine the immunological basis of severe illness at the site of infection. Infection and immune response were tracked through blood, nasal swabs and nasal wash samples collected from all patients. Sampling began when a patient first sought medical attention and was repeated on days 3, 7, 10 and 28. Forty-two cytokines and antibodies circulating against influenza viruses were also measured.
Overall, 19 patients were admitted to the hospital and four of those were admitted to the ICU.
Patients with elevated levels of three cytokines (MCP-3, interferon alpha 2, and interleukin 10) early during their infection were more likely to develop severe influenza symptoms and require hospitalization. Cytokine levels helped predict influenza-related complications regardless of patient age, influenza strain, the ability of the virus to replicate and other factors. Inflammation driving by the innate immune response was regulated by the cytokines involved.
Regardless of subtype, both children and adults were successful at eliminating the virus and children had a more aggressive inflammatory response, according to the researchers.
“The fact that the innate immune response was stronger in the airways of children than adults was a surprise,” Christine Oshansky, PhD, a postdoctoral fellow at St. Jude Children’s Research Hospital, said in the release. “Previous studies using different measures reported that children mounted a weaker immune response.”
Disclosure: The study was funded in part by the National Institute of Allergy and Infectious Diseases and the NIH.