Researchers studying critically ill children with traumatic injuries have identified an immune marker that predicts which patients are likely to develop a hospital-acquired infection. The study, led by clinician-scientists at Nationwide Children's Hospital and published online in June in the journal Shock, is part of several larger efforts that could lead to the clinical implementation of quick-turnaround immune function tests and treatments to prevent or reverse immune system damage following critical illness or injury in pediatric patients.
Hospital-acquired, or nosocomial, infections pose a threat to any patient, but people who've suffered a traumatic injury have the highest risk of all, says Mark W. Hall, MD, senior author of the new study and division chief of Critical Care Medicine at Nationwide Children's. Dr. Hall and his colleagues have spent more than a decade studying this phenomenon and have honed in on a problem within the immune system as a possible contributor.
"With a normal immune response, the body responds to pathogens and eliminates them before they cause an infection. But in many forms of critical illness, we see the immune system unable to do those things," he says. Studies in adults with traumatic injuries have found that immune function is decreased in those patients, but this is the first data to show that the same thing happens in critically injured children.
For the study, the researchers collected blood samples from 21 healthy children and 76 critically injured children 18 years of age or younger. In a test tube, they exposed each sample to lipopolysaccharide (LPS), a known stimulant of the immune response. When healthy cells are exposed to LPS, it prompts the production of TNF-alpha, a type of protein called a cytokine that is part of the first line of defense in the body's innate immune system.
When they analyzed the immune response in the lab, they found that blood cell samples from the
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Nationwide Children's Hospital