Integrative Analyses of Single-Cell RNA-Sequencing and Bulk RNA-Sequencing Reveal Prognostic Markers of Peripheral Blood Mononuclear Cells in Patients with Cardiogenic Shock Receiving Venous-Arterial Extracorporeal Membrane Oxygenation Support Collected before Venous-Arterial Extracorporeal Membrane Oxygenation Establishment.

The impact of changes in peripheral blood mononuclear cells (PBMCs) on the prognosis of patients with cardiogenic shock (CS) receiving venous-arterial extracorporeal membrane oxygenation (VA-ECMO) remains unclear. A single-cell RNA-sequencing (scRNA-seq) and a bulk RNA-sequencing (bulk RNA-seq) data sets of pre-ECMO PBMCs of CS patients were obtained from the gene expression omnibus database, which were analyzed using the "Seurat" and "limma" packages, respectively. The counts of different PMBC cell types, differential expression genes (DEGs), pathway enrichment analysis, cell-cell communication analysis, pseudotime analysis, and immune cell infiltration analysis were compared between VA-ECMO groups with different prognoses. The intersectional DEGs of the two data sets were screened. PBMCs were collected from VA-ECMO patients for experimental verification. For scRNA-seq analysis, ten kinds of PBMCs were identified, and B and NK/NKT cells which had significant differences in cell counts across groups were further divided into four subsets. The counts of B and NK/NKT cells with high expression levels of HSPA1B were higher in the poor-prognosis group, which was consistent with the bulk RNA-seq analysis. Pseudotime analysis also indicated that B-HSPA1B cells gradually increased in the poor-prognosis group. HSPA1B was found to be the intersectional upregulated DEG in both data sets, which was consistent with the experimental verification using clinical samples. The increased counts of B and NK/NKT cells as well as high expression levels of HSPA1B in these cell types or in the total pre-ECMO PBMCs were predictors of poor prognosis.