Single Cell And Spatial Transcriptomics Of Blood And Biopsies Reveals Enhanced Alloantigen Presenting Function And T-follicular Helper Cell (tfh) Expansion Early After Pediatric Liver Transplantation
1Childrens Hospital of Pittsburgh of UPMC, Pittsburgh, PA, 2University of Pittsburgh Medical Center, Pittsburgh, PA
Meeting: 2022 American Transplant Congress
Abstract number: 9076
Keywords: Antibodies, B cells, Liver transplantation, Rejection
Topic: Clinical Science » Liver » 61 - Liver: Pediatrics
Session Information
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: We have previously reported enhanced B-cell presentation of donor antigen during early T-cell mediated liver transplant (LT) rejection.
*Methods: To characterize B-cell related immunological mechanisms as predictors of late LT outcomes in children, we tested a) single cell RNA sequencing (scRNAseq) of peripheral blood leukocytes (PBL) obtained before and within 90 days after LT from 18 children, of whom 9 experienced early acute cellular rejection (R), and 9 did not (NR) (10XGenomics), b) spatial transcriptomics of corresponding FFPE biopsies from 5 R and 2 NR (Visium, 10XGenomics), c) donor-specific Tfh (CD4+CD45RO+CXCR5+) and donor-specific B-cells in PBL from 12 independent children with LT, and d) donor-specific anti-HLA antibodies (DSA).
*Results: MHC class II DSA developed early, disappearing by month 12 in 4 R and 1 NR among 18 LT. Preliminary scRNAseq analysis revealed upregulated B-cell receptor component CD79b, and upregulated inflammatory marker S100A2 and downregulated suppressive marker CD163 in CD14+monocytes in R compared with NR. The Y-chromosome-encoded DDX3Y gene was also upregulated in B-, T-, and NK-cells and CD14+monocytes among R compared with NR. Six of 18 LT were female recipients of a male allograft, including 2R and 4NR. These genes were not differentially expressed before LT. Spatial transcriptomics revealed upregulated gene sets for Immunoglobulin production via mechanisms including affinity maturation, antigen receptor signaling via B-cell and T-cell receptors, and antigen processing and presentation (GO terms 0002381,0019881, and 0050851) in biopsies from R compared with NR. This enrichment occurred in non-hepatocyte-rich regions with B-cell, dendritic cell and Langerhans like cells. Among 6 independent LT tested early after LT, donor-specific B-cells and Tfh increased among 3 R compared with 3 NR. Among 6 independent LT tested >1 year post-LT during a rejection-free period, frequencies of donor-induced Tfh, and donor-reactive CD40L+Tfh were higher in 3 children with DSA and prior early rejection compared with 3 children without either feature.
*Conclusions: High-dimensional molecular profiling of blood and biopsies reveals early activation of antigen presenting and antibody production mechanisms as possible contributors to late antibody-mediated allograft injury in pediatric LT. Detailed longitudinal analysis may also confirm gender effects.
To cite this abstract in AMA style:
Sindhi R, Ashokkumar C, Ningappa M, Rajasundaram D, Higgs BW, Xu Q, Zeevi A, Reyes-Mugica M. Single Cell And Spatial Transcriptomics Of Blood And Biopsies Reveals Enhanced Alloantigen Presenting Function And T-follicular Helper Cell (tfh) Expansion Early After Pediatric Liver Transplantation [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/single-cell-and-spatial-transcriptomics-of-blood-and-biopsies-reveals-enhanced-alloantigen-presenting-function-and-t-follicular-helper-cell-tfh-expansion-early-after-pediatric-liver-transplantation/. Accessed May 8, 2025.« Back to 2022 American Transplant Congress