Identification of host endotypes using peripheral blood transcriptomics in a prospective cohort of patients with endocarditis

Abstract

BackgroundHost responses to infection are a major determinant of outcome. However, the existence of different response profiles in patients with endocarditis has not been addressed. Our objective was to apply transcriptomics to identify endotypes in patients with infective endocarditis. MethodsThirty-two patients with infective endocarditis were studied. Clinical data and a blood sample were collected at diagnosis, and RNA sequenced. Gene expression was used to identify two clusters (endocarditis endotypes EE1 and EE2). RNA sequencing was repeated after surgery. Transcriptionally active cell populations were identified by deconvolution. Differences between endotypes in clinical data, survival, gene expression and molecular pathways involved were assessed. Identified endotypes were recapitulated in a cohort of COVID19 patients. Results18 and 14 patients were assigned to EE1 and EE2 respectively, with no differences in clinical data. Patients assigned to EE2 showed an enrichment in genes related to T-cell maturation and a decrease in the activation of the STAT pathway, with higher counts of active T-cells and lower counts of neutrophils. Fourteen patients (9 in EE1 and 5 in EE2) were submitted to surgery. Surgery in EE2 patients shifted gene expression towards a EE1-like profile. In-hospital mortality was higher in EE1 (56% vs 14%, p=0.027) with adjusted hazard ratio of 12.987 (95% confidence interval 3.356 – 50]. Translation of these endotypes to COVID19 and non-COVID septic patients yielded similar results in cell populations and outcome. ConclusionsGene expression reveals two endotypes in patients with acute endocarditis, with different underlying pathogenetic mechanisms, response to surgery and outcome.