Aberrant Newborn T Cell and Microbiota Developmental Trajectories Predict Respiratory Compromise During Infancy

Neonatal immune-microbiota co-development is poorly understood, yet age appropriate recognition of - and response to - pathogens and commensal microbiota is critical to health. In this longitudinal study of 148 preterm and 119 full-term infants from birth through one year of age, we found that post menstrual age or weeks from conception is a central factor influencing T cell and mucosal microbiota development. Numerous features of the T cell and micro biota functional development remain unexplained; however, by either age metric and are instead shaped by discrete perinatal and postnatal events. Most strikingly, we establish that prenatal antibiotics or infection disrupt the normal T cell population developmental trajectory, influencing subsequent respiratory microbial colonization and predicting respiratory morbidity. In this way, early exposures predict the postnatal immune-microbiota axis trajectory, placing infants at later risk for respiratory morbidity in early childhood.