"It's been known that the influenza virus does something to suppress host immune function, which can facilitate development of deadly secondary bacterial pneumonias," said McCullers. "But we haven't known what that was or why it happens."
McCullers' research – conducted at his National Institutes of Health-funded laboratory at St. Jude Children's Research Hospital by UTHSC graduate student Hazem Ghoneim, a PhD candidate -- used advanced techniques to differentiate types of alveolar macrophages found in the lungs and airways. Researchers found that of the three types identified, only one is truly capable of fending off secondary bacterial infection. This population of macrophages, labeled the resident alveolar macrophages, is depleted during a flu infection.
"We found that influenza is specifically killing these true alveolar macrophages," said McCullers. "The window of time someone is susceptible to secondary infections corresponds with the time it takes for the other two types of alveolar macrophages to differentiate so they are then able to fight off the infection."
Childhood Pneumonia Rate Higher in Urban Apartments: Study
In urban modern cities, the incidence of childhood pneumonia is still high, reveals study.
In urban modern cities, the incidence of childhood pneumonia is still high, reveals study.
"This discovery provides a roadmap for developing immunotherapies that can supplement the natural defenses of our body when they are at their weakest. Influenza and pneumonia are the seventh leading cause of death in the U.S., and we desperately need research such as this to improve our armamentarium," said McCullers.
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Influenza Infection Increases Likelihood of Bacterial Pneumonia
Influenza infection boosts the risk of bacterial pneumonia by about 100-fold, say University of Michigan researchers.
Influenza infection boosts the risk of bacterial pneumonia by about 100-fold, say University of Michigan researchers.
