Prospective Tracking of Donor-Reactive T-Cell Clones in the Circulation and Rejecting Human Kidney Allografts

• Published in: Frontiers in immunology Vol. 12; p. 750005
• Main Authors: Aschauer, Constantin, Jelencsics, Kira, Hu, Karin, Heinzel, Andreas, Gregorich, Mariella Gloria, Vetter, Julia, Schaller, Susanne, Winkler, Stephan M., Weinberger, Johannes, Pimenov, Lisabeth, Gualdoni, Guido A., Eder, Michael, Kainz, Alexander, Troescher, Anna Regina, Regele, Heinz, Reindl-Schwaighofer, Roman, Wekerle, Thomas, Huppa, Johannes Bernhard, Sykes, Megan, Oberbauer, Rainer
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 14.10.2021
• Subjects: Allografts - immunology; alloreactivity; Female; Graft Rejection - immunology; Humans; Immunology; kidney transplant; Kidney Transplantation; Male; network analysis; next generation sequencing; Receptors, Antigen, T-Cell - genetics; Receptors, Antigen, T-Cell - immunology; rejection; T-cell receptor; T-Lymphocytes - immunology; Tissue Donors; T-cell receptor; kidney transplant; network analysis; alloreactivity; next generation sequencing; rejection
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2021.750005

Antigen recognition of allo-peptides and HLA molecules leads to the activation of donor-reactive T-cells following transplantation, potentially causing T-cell-mediated rejection (TCMR). Sequencing of the T-cell receptor (TCR) repertoire can be used to track the donor-reactive repertoire in blood and tissue of patients after kidney transplantation. In this prospective cohort study, 117 non-sensitized kidney transplant recipients with anti-CD25 induction were included. Peripheral mononuclear cells (PBMCs) were sampled pre-transplant and at the time of protocol or indication biopsies together with graft tissue. Next-generation sequencing (NGS) of the CDR3 region of the TCRbeta chain was performed after donor stimulation in mixed lymphocyte reactions to define the donor-reactive TCR repertoire. Blood and tissue of six patients experiencing a TCMR and six patients without rejection on protocol biopsies were interrogated for these TCRs. To elucidate common features of T-cell clonotypes, a network analysis of the TCR repertoires was performed. After transplantation, the frequency of circulating donor-reactive CD4 T-cells increased significantly from 0.86 ± 0.40% to 2.06 ± 0.40% of all CD4 cells (p < 0.001, mean dif.: -1.197, CI: -1.802, -0.593). The number of circulating donor-reactive CD4 clonotypes increased from 0.72 ± 0.33% to 1.89 ± 0.33% (p < 0.001, mean dif.: -1.168, CI: -1.724, -0.612). No difference in the percentage of donor-reactive T-cells in the circulation at transplant biopsy was found between subjects experiencing a TCMR and the control group [p = 0.64 (CD4 ), p = 0.52 (CD8 )]. Graft-infiltrating T-cells showed an up to six-fold increase of donor-reactive T-cell clonotypes compared to the blood at the same time (3.7 0.6% and 2.4 1.5%), but the infiltrating TCR repertoire was not reflected by the composition of the circulating TCR repertoire despite some overlap. Network analysis showed a distinct segregation of the donor-reactive repertoire with higher modularity than the overall TCR repertoire in the blood. These findings indicate an unchoreographed process of diverse T-cell clones directed against numerous non-self antigens found in the allograft. Donor-reactive T-cells are enriched in the kidney allograft during a TCMR episode, and dominant tissue clones are also found in the blood. Clinicaltrials.gov: NCT: 03422224 (https://clinicaltrials.gov/ct2/show/NCT03422224).