Abstract 11992: Novel Immune Profiling Utilizing Single-Cell Mass Cytometry in Pediatric Heart Failure

Abstract

Introduction: Pediatric end-stage heart failure (ESHF) is a diverse disease with significant morbidity. Many children are supported with ventricular assist devices (VAD), adding further high risk of complication. Specific markers for adverse events are unknown. Emerging evidence suggests the presence of inflammation and immune dysfunction in ESHF. Improved understanding of systemic immune dysfunction is a first step towards identifying biomarkers of ESHF. We hypothesize that the distribution and signaling of innate and adaptive immune cells differ in pediatric ESHF and healthy controls. Methods: A high-dimensional, single-cell mass cytometry immuno-assay was used to quantify 247 cell signaling events in whole blood from children with ESHF (n=18) and healthy controls (n=12). Cell signaling was assessed at baseline and after stimulation. Multivariate regularized regression modeling with Elastic Net (EN) was used to identify differences between groups (fig. 1A). Secondary analyses evaluated effect of ESHF+VAD (n=6). Statistical significance was established using Leave one out cross validation. Results: We identified an EN model that stratified ESHF vs. controls with high accuracy (fig. 1B). Model analysis revealed cell-type and signaling differences that spanned innate and adaptive immune components. ESHF showed depressed endogenous gdT cell frequency, pERK signaling in ncMCs, and elevated pSTAT3 and pSTAT4 in CD4+ T cells in response to cytokine stimulation. Additionally, the model predicted differences in ESHF vs. ESHF+VAD with high accuracy (fig. 1C-D). Conclusions: Comprehensive single-cell analysis identified a robust immune signature of pediatric ESHF that was further modulated by presence of a VAD. Individual features revealed novel innate and adaptive immune dysfunction. Future prospective studies will be key to identifying immunological biomarkers that facilitate clinical decisions and predict complications in pediatric ESHF.