Immune cell heterogeneity in chronic antibody mediated kidney allograft rejection revealed by single cell RNA sequencing

Kidney transplantation is the gold standard treatment for end-stage kidney disease; however allograft rejection remains a major challenge. Antibody-Mediated Rejection (ABMR) is a complex immunological process that involves interactions between immune cells and renal parenchymal cells. Despite improvements in immunosuppressive therapies, chronic rejection and the adverse effects of long-term immunosuppression necessitate a deeper understanding of rejection mechanisms. This study aimed to utilize single-cell RNA sequencing (scRNA-seq) to analyze the peripheral immune landscape in ABMR and identify key cell populations and molecular pathways involved in its pathogenesis. Publicly available scRNA-seq datasets (GSE190329, GSE171374) of peripheral blood cells from kidney transplant recipients with chronic ABMR (cABMR) and stable controls were analyzed. Data preprocessing, normalization, and integration were performed using Seurat and Harmony. Differential gene expression and pathway enrichment analysis were conducted to explore the molecular mechanisms, while cell–cell communication was analyzed using the CellChat package. A total of 28,131 high-quality single cells were retained for analysis. Activated neutrophils, T cells, and monocytes were the dominant cell types in patients with cABMR and controls. Pathway enrichment analysis revealed significant activation of the NF-kappa B, IL-17, and cytokine-cytokine receptor interaction pathways in cABMR immune cells. Notably, robust intercellular communication was detected, especially between activated neutrophils, monocytes, and B cells, with prominent signaling axes involving CXCL8–CXCR2 and ANXA1–FPR1. This study provides a descriptive, hypothesis-generating characterization of peripheral immune cell interactions and signaling pathways associated with cABMR. Further validation in larger cohorts with graft-level and functional data is required.