Brooke Quertermous, MD, on using urine biomarkers to identify severity of respiratory infections in infancy

Urine F2-isoprostanes, a marker of oxidative stress, were associated with more severe viral acute respiratory infections (ARIs) in infants across 2 independent cohorts, according to findings presented at the 2026 Pediatric Academic Societies (PAS) Meeting.^1,2

In an interview with Contemporary Pediatrics, Brooke Quertermous, MD, fellow in the Division of Pediatric Hospital Medicine at Monroe Carell Jr. Children’s Hospital at Vanderbilt, discussed how the findings may help researchers better understand why some previously healthy infants experience more severe respiratory disease than others.

The study evaluated urine F2-isoprostanes (F2-IsoPs) in infants enrolled in 2 cohorts: INSPIRE, a population-based birth cohort of previously healthy term infants, and TCRI, a cohort of infants evaluated during health care encounters for viral respiratory illness.

Investigators measured urine F2-IsoPs using liquid chromatography–mass spectrometry and assessed associations with markers of illness severity. In INSPIRE, higher urine F2-IsoPs were associated with higher Respiratory Severity Scores (RSS). In TCRI, higher urine F2-IsoPs were associated with increased need for supplemental oxygen during illness.

Researchers examine oxidative stress and respiratory severity

Quertermous said the study was designed to evaluate whether oxidative stress may contribute to severe viral respiratory disease in infancy.

“The study we’re going to be talking about today was essentially looking at f2 isoprostanes, which are a marker of oxidative stress, to see if they can potentially be a biomarker for the severity of acute viral respiratory infections in infancy,” Quertermous said.

According to the study, the INSPIRE cohort included 331 infants, and the TCRI cohort included 51 infants. In adjusted analyses, urine F2-IsoPs remained significantly associated with higher RSS in the INSPIRE cohort (β = 0.31; 95% CI, 0.02-0.61; P = .04).

Among infants in TCRI, median urine F2-IsoPs were higher in those requiring supplemental oxygen compared with those who did not require oxygen support (7.1 ng/mg creatinine vs 3.7 ng/mg creatinine; P = .03).

Quertermous said the findings support additional investigation into oxidative stress pathways during infant respiratory infections.

“As a fellow in pediatric hospital medicine, I see a lot of infants who have very severe presentations to these disorders,” she said. “We know of some risk factors, such as prematurity or having underlying medical conditions that might put some infants at risk for having these disorders, but we also see healthy children who don’t have an underlying reason as to why they might get so sick from these viruses.”

She added that the study was intended to provide “preliminary data to set up for future studies to determine what, if any, effect oxidative stress has on potentially the pathophysiology of these severe respiratory illnesses.”

Noninvasive testing may support future pediatric research

Because urine F2-IsoPs can be obtained noninvasively, investigators noted potential advantages for pediatric research settings.

“Anytime we think about research studies for children and infants, any kind of test, if we could be noninvasive, that is an ideal kind of test for them,” Quertermous said. “This can be measured completely noninvasively.”

However, she noted that broader clinical implementation remains limited because the assay currently requires specialized laboratory testing.

“We’re probably not quite there yet with clinical utility,” Quertermous said, citing the need for mass spectrometry and specialized laboratory expertise.

Still, investigators said the consistent findings across 2 cohorts strengthen the evidence supporting F2-IsoPs as a potential biomarker of severe viral respiratory illness in infancy.

“I think the finding in 2 different cohorts really kind of strengthens the probability that these F2 isoprostanes could potentially be used as a biomarker for these severe respiratory illnesses,” Quertermous said.

Future studies may explore asthma and recurrent wheeze

Quertermous said that future research will evaluate whether oxidative stress may contribute to recurrent wheeze or the development of asthma after early-life respiratory infections.

“A big question that we as hospitalists and pediatricians globally have is which children with respiratory infections in early life are going to go on to develop asthma or recurrent wheeze in childhood,” Quertermous said.

She added that additional work is needed before urine F2-IsoPs could become part of clinical decision-making.

“This data is really preliminary, and so I think we have several steps to go before this would be something that would be easily implemented in a clinical setting,” Quertermous said.

Disclosure: Quertermous reports no relevant disclosures.

References

1. Quertermous B, Gebretsadik T, Snyder B, et al. Urine F2-isoprostanes: a potential biomarker for the severity of viral acute respiratory infections in infancy. Presented at: PAS 2026 Meeting; April 24-27, 2026; Boston, MA.

2. Quertermous B. Video. interview with Contemporary Pediatrics. May 7, 2026. Accessed May 7, 2026.