Oral Presentation Australasian Cytometry Society 43rd Annual Conference and Workshop

T-follicular-helper and B memory cells in antibody-mediated rejection in kidney transplantation. (#26)

Brenda Maria Rosales 1 , Bavani Gunasegaran 1 , Helen McGuire 1 2 , Barbara Fazekas de St Groth 1 , Kate Wyburn 1 3
  1. The University of Sydney, Camperdown, NEW SOUTH WALES, Australia
  2. Ramaciotti Facility for Human Systems Biology, Sydney
  3. Renal Medicine and Transplantation, Royal Prince Alfred Hospital, Sydney, NSW, Australia

Aims: T follicular helper cells (Tfh) and B memory cells have been associated with donor-specific antibody (DSA) and implicated in antibody-mediated rejection (ABMR). We sought to describe immune cell subsets that characterise ABMR recipients in a well-described clinical cohort. Methods: We profiled immune cell subsets in kidney transplant recipients with ABMR against age- and sex-matched Stable recipients with no rejection. Pre- and 3-month post-transplant samples were immunophenotyped in a 40-monoclonal-antibody panel using cytometry by time-of-flight. Immune cell subsets were manually gated using FloJo and proportions compared using significance analysis for microarray to identify partitioning cell subsets (5%FDR). Results: Of the 9 ABMR recipients (4 women, median age-at-transplant 47 years), 5 had pre-transplant DSA of which 4 received desensitisation therapy, 1 had PRA>80%, and 4 developed de-novo-DSA. None experienced T-cell mediated rejection. Median time to ABMR was 41 days (IQR=10-358), 5/9 ABMR recipients experienced rejection within 3 months post-transplant. Of the 9 Stable recipients (4 women, median-age-at-transplant 48 years), 5 had pre-transplant DSA of which 2 received desensitisation therapy, 1 had PRA>80%, and 3 developed de-novo-DSA. We found 9 cell subsets distinguished between ABMR and Stable recipient pre-transplant including, central memory Tfh (CD3+CD4+CD25-CD45RO+CXCR5+CCR7hiPD1lo), Th17-like Tfh (CD3+CXCR5+CXCR3-CCR6+), and B memory (CD19+CD20+CD27+) cells (Figure 1). Tfh cell subset proportions decreased in post-transplant compared to pre-transplant samples in Stable recipients but were maintained across ABMR pre- and post-transplant samples. Conclusions: T follicular cell subset and B memory cell proportions characterise ABMR recipients pre-transplant and are maintained post-transplant.

Figure 1: Significance analysis for microarray for pre-transplant samples of ABMR and Stable kidney transplant recipients6148062b2057a-Figure1.png