Biomarkers of Growth Faltering and Neurodevelopmental Delay in Children who are HIV-Exposed but Uninfected: A Systematic Review

Introduction: Children who are HIV-exposed but uninfected (CHEU) are at risk of linear growth faltering and neurodevelopmental delay. Circulating biomarkers associated with these adverse outcomes may elucidate pathways of injury. Objective: To identify biomarkers associated with growth faltering and neurodevelopmental delay in CHEU. Methods: We performed a systematic review of electronic databases MEDLINE (1946-April 2021), EMBASE (1974-April 2021), Scopus (2004-April 2021), and PubMed (1985-April 2021), following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO, registration number CRD42021238363). Results: We found seven studies associating biomarker abnormalities and growth outcomes in CHEUs and two studies on biomarker abnormalities and neurodevelopmental delay. Biomarker abnormalities associated with growth restriction were: C-reactive protein (CRP), tumour necrosis factor (TNF), interferon-gamma (IFN-γ), interleukin (IL)-12p70, IFN-γ-induced protein-10 (CXCL10/IP-10), lipopolysaccharide binding protein (LBP), insulin-like growth factor-1 (IGF-1), and IGF-binding protein-1 (IGFBP-1). Biomarkers associated with motor, language, and cognitive delay were CRP, IFN-γ, IL-1β, -2, -4, -6, -10, -12p70, neutrophil gelatinase-associated lipocalin (NGAL), granulocyte-macrophage colony-stimulating factor (GM-CSF), and matrix metalloproteinase- 9 (MMP-9). Conclusion: Elevated markers of inflammation (acute phase reactants, pro-inflammatory cytokines, chemokines) and intestinal microbial translocation are associated with growth faltering. Elevated markers of inflammation are associated with adverse neurodevelopment.