PROJECT SUMMARY/ABSTRACT
Benjamin Lee, MD – Principal Investigator (PI)
Childhood undernutrition affects approximately 200 million children around the world and is associated with
increased risk of child mortality from infectious diseases. It is generally accepted that undernutrition, as
manifested by growth impairment, causes functional immune deficiency that increases susceptibility to severe
infections. However, other than in the most extreme form of severe acute malnutrition (SAM), an immunologic
basis for this increased risk in undernourished children has yet to be convincingly demonstrated. This may be
due in part to previous methodologic limitations, such as reliance on cross-sectional evaluations that cofounded
identification of children at highest risk and use of rudimentary methods of immune assessment. This project will
address this knowledge gap via longitudinal evaluation of underexplored aspects of pediatric immune
development in undernourished and healthy children from a birth cohort study conducted in Dhaka, Bangladesh
(PROVIDE). In Aim 1, the multidisciplinary research team will first use stool metagenomic sequencing to
investigate the critical contribution of gut microbiota maturation to growth phenotype during the first 2 years of
life, and persistence of these effects into later childhood. Children with SAM from this community have previously
demonstrated impaired microbiota maturation. This study will assess whether similar perturbations, along with
measures of diversity, taxonomic community structure, and metabolic pathways may affect children with other
forms of growth impairment, including growth failure, stunting, and underweight. In Aim 2, the project will evaluate
measures of T cell diversity and systemic inflammation in these children, along with exploratory analyses using
single-cell proteogenomics to identify immune cell profiles unique to each growth phenotype. Finally, the impact
of the gut microbiota on these immune outcomes will be investigated. This project will use careful case selection
in a well-characterized longitudinal cohort to address critical knowledge gaps relating to undernutrition,
microbiota development, and development and maintenance of immune diversity. The knowledge gained herein
will provide a major contribution to basic understanding of fundamentally important aspects of the “first 1000
days of life,” the window period from conception to age 2 most critical for establishment of healthy growth and
development in children. Ultimately, this work may help inform needed interventions to improve children and
development, particularly in resource-limited settings where undernutrition and child mortality due to infections
is most prevalent.