Bronchiolitis—the most common lung infection in young children, and which is most often caused by respiratory syncytial virus, or RSV—is the leading cause of hospitalizations in U.S. infants, and about 30% of those with severe bronchiolitis later develop asthma. A team led by investigators at Massachusetts General Hospital (MGH) has uncovered four distinct molecular subtypes of RSV bronchiolitis and has linked a certain subtype to a higher asthma risk.
"While bronchiolitis has been considered a single disease with similar mechanisms, emerging evidence has suggested that bronchiolitis consists of multiple disease subgroups," says lead author Yoshihiko Raita, MD, MMSc, a researcher in the MGH Department of Emergency Medicine. "But our limited understanding of RSV bronchiolitis, and how it varies, has held up efforts to develop RSV bronchiolitis treatment and asthma prevention strategies."
To provide insights, Raita and his colleagues analyzed diverse clinical, genetic and molecular data from 221 infants hospitalized with RSV bronchiolitis who were followed until five years of age. The scientists gathered information on the viruses that had infected the children, as well as information on the microbes, metabolites and immune response-related molecules present in the children's nasal passages.