Researchers identify markers of more serious cases

Respiratory syncytial virus (RSV) remains the leading cause of hospitalization in young children, leading to respiratory problems such as bronchiolitis and pneumonia. However, the reasons why some children experience only mild symptoms while others experience severe illness are not well understood.

To better understand what happens in these cases, clinician researchers at Brigham and Women’s Hospital, a founding member of the Mass General Brigham Health System, and Boston Children’s Hospital analyzed samples of patients’ respiratory tract and blood, revealing distinct changes in children with severe forms. cases of RSV, including an increase in the number of natural killer (NK) cells in their airways.

The descriptive study, which focuses on understanding the underpinnings of serious illness, could help lay the foundation for identifying new targets for future treatments. The results are published in Scientific translational medicine.

“As a doctor, I help treat children who have the most severe symptoms, and as a researcher, I am determined to understand why they get so sick,” said corresponding author Melody G. Duvall, MD, Ph.D., of the Division of Pulmonary and Critical Care Medicine at Brigham and Women’s Hospital (BWH) and the Division of Critical Care Medicine at Boston Children’s Hospital.

“NK cells are important first responders during viral infection, but they can also contribute to lung inflammation. Interestingly, our results are consistent with data from some COVID-19 studies, which have reported that Patients with the most severe symptoms also had increased NK cells in their airways. Along with previous studies, our data links NK cells to severe viral disease, suggesting that these cellular pathways merit further investigation.

Duvall and colleagues, including lead author Roisin B. Reilly of the Division of Pulmonary and Critical Care Medicine at BWH, examined samples from 47 children critically ill with RSV, analyzing immune cells found in their airways and their peripheral blood. Compared to uninfected children, those with severe disease had high levels of NK cells in their airways and fewer of these cells in their blood. Additionally, they found that the cells themselves were altered, both in appearance and in their ability to carry out their immunological function of killing diseased cells.

Duvall and co-authors have previously described a post-pandemic increase in pediatric RSV infections. While clinicians can only provide supportive care to the most seriously ill children, RSV vaccines are now available for children 19 months and younger, adults 60 years and older, and pregnant people.

In addition to Duvall and Reilly, authors include Saïsha K. Ramdour (BWH), Mary E. Fuhlbrigge (BWH), Luciana P. Tavares (BWH), Steven J. Staffa (BCH), Jocelyn M. Booth (BCH), Nandini Krishnamoorthy (BWH) and Bruce D. Levy (BWH).