Immune Responses to the Flu Vary

Why Immune Responses of People
Exposed to the Flu Vary Significantly

Research Scientists From Duke University Medical Center Report

Why do some folks who take every precaution still get the flu, while others never even catch the common cold? It comes down to a person's immune system response to the flu virus, say researchers .

Research scientists from Duke University Medical Center and the Duke Institute for Genome Sciences & Policy used genomics to begin to unravel what in our complex genomic data accounts for why some get sick while others don't. The study findings appears in PLoS Genetics online.

An analysis group used several methods, including a pattern recognition algorithm previously developed for satellite imaging of the environment to discover the genomic signatures associated with immune response and flu symptoms. One of the principal analysis methods was a pattern-recognition tool. Using these genomic signatures, researchers compared the responses of previously healthy participants inoculated with the flu, and found significant and complex immune responses in both people who got sick and those who did not.

The gene expression data identifies how the immune system reacts and orchestrates its response to the flu virus, which dictates whether people get sick.

"We looked at over 22,000 genes in 267 blood samples," said the researchers "No study of this magnitude has ever been done on human immune response." The study reveals what happens after virus exposure. "It also points out, importantly, that remaining asymptomatic in the face of an exposure to a virus is an active process in the immune system, and we can now begin to probe the underlying biology to resisting infection," they said.

The team inoculated 17 healthy individuals with the flu virus and about half of them got sick.

They then collected gene expression data from each individual at 16 time points over 132 hours. These data provided a clear picture of the gene expression over time in those who developed flu symptoms and those who did not.

In theory, if scientists can understand what happens at the level of the genome that makes people more or less susceptible to viral illness, they could potentially develop therapies to prevent the illness. Hero said the inflammatory genomic signature that differentiated the well group from the sick group was measurable up to about 36 hours before peak flu symptoms developed. It may, therefore, be possible to detect illness early, allowing people to take precautions and perhaps even prevent the worst symptoms.

The work was funded by the DARPA Predicting Health and Disease program under a grant to a team at Duke and Michigan.

Story Source: University of Michigan.

Journal Reference:
"Temporal Dynamics of Host Molecular Responses Differentiate Symptomatic and Asymptomatic Influenza A Infection."
PLoS Genetics, 2011;

University of Michigan (2011, August 25).
"Wide gap in immune responses of people exposed to the flu."

This article is for informational and educational purposes only, and is not intended to provide medical advice, diagnosis or treatment. Contact your doctor or healthcare professional for medical and nutritional consultation.