Clinical Assistant Professor Stanford University Palo Alto, California, United States
Abstract:
Introduction: Pediatric end-stage heart failure (ESHF) is a diverse disease with significant morbidity and mortality. Many of these children are supported with ventricular assist devices (VAD), adding further high risk of complications. Specific markers for adverse events in both sets of patients 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 cell distribution and signaling activities of the innate and adaptive immune system differ in pediatric ESHF when compared to healthy children.
Methods: A high-dimensional, single-cell mass cytometry immuno-assay was applied to quantify 247 innate and adaptive cell signaling events in whole blood samples from children with ESHF (n=18) and healthy controls (n=12). Single-cell frequency and signaling activities were assessed at baseline and in response to cytokine stimulation. A multivariate regularized regression modeling approach with Elastic Net (EN) was employed to identify differences in innate and adaptive immune responses between healthy children and those with ESHF (fig. 1A). Secondary analyses evaluated the effect of ESHF+ long-term VAD (n=6). Statistical significance was established using Leave one out cross validation.
Results: We identified an EN model that stratified patients with ESHF vs. controls with high accuracy (fig. 1B). Model analysis revealed cell-type and signaling-specific differences between ESHF and healthy controls that spanned innate and adaptive immune components. ESHF showed depressed endogenous gamma-delta cell frequency, pERK signaling in non-classical monocytes, 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 as well (fig. 1D).
Conclusion: Comprehensive single-cell analysis of the systemic immune response in pediatric patients identified a robust immune signature of ESHF, and this was further modulated by the presence of a long-term VAD. Individual features revealed novel innate and adaptive immune cell dysfunction. Future prospective studies will be key to identifying immunological biomarkers that facilitate clinical decision-making and predict complications in pediatric ESHF and VAD.
