Plasma lipopolysaccharide levels predict mortality in acutely ill children in Low- and Middle-Income Countries.

Childhood mortality remains high in low-resource settings, where environmental enteric dysfunction (EED) is prevalent. Peripheral blood bacterial lipopolysaccharides (LPS) are potential biomarkers of intestinal microbial translocation and inflammation; however, the effects of LPS translocation on mortality in this context remains unexplored. We investigate the association between plasma LPS and mortality among 638 acutely ill hospitalised children and compare them to 251 well community peers in a nested case-cohort (NCC) conducted between November 2016 and January 2019 across 9 sites in 6 countries in sub-Saharan Africa and South Asia. Higher levels of plasma LPS and inflammatory biomarkers (fecal calprotectin, plasma myeloperoxidase, and CD14) are associated with elevated 90-day mortality, and those associations are independent of wasting status. Non-survivors with high plasma LPS exhibit elevated gram-negative enteric microbiota, increased fecal biomarkers of EED, systemic inflammatory proteins, and differentially expressed proteins linked to the Insulin-like growth factor (IGF) nutritional axis, Interleukin-1 and collagen regeneration. Cellular interaction network models deconvoluted from a single-cell transcriptomic dataset enable an exploratory investigation of systemic immune responses and epithelial-immune cells crosstalk active in pathways leading to mortality. This knowledge can guide the identification of potential therapeutic signaling pathways in settings with high EED and malnutrition.