Abstract: FR-PO1011

Development of De Novo Donor-Specific Antibodies, Intra-Graft B Cell Populations, and Allograft Function and Morphology in a Rat Model of Non-Adherence to Therapy after Renal Transplantation

Session Information

Category: Transplantation

  • 1701 Transplantation: Basic and Experimental

Author

  • Kühne, Louisa, University Hospital Regensburg, Regensburg, Germany
Background

Introduction: Non-adherence to immunosuppressive therapy has been associated with de novo donor-specific antibodies (dnDSA) and antibody-mediated rejection (ABMR). The aim of this study was to investigate the development of dnDSA, intra-graft leukocyte and specifically B cell subpopulations, as well as allograft function and morphology in a model of renal transplant simulating non-adherence.

Methods

Methods: We used a rat model of renal transplantation (Brown Norway -> Lewis) with intermittent cyclosporine A administration (CyA 5mg/KG) on every other day (daily application until d7), to simulate non-adherence. Transplanted rats were sacrificed after 6, 28, and 56 days. DnDSA were measured by flow crossmatch and complement-dependent cytotoxicity (CDC) assay. DSA IgG subclasses were also assessed. Flow cytometry was used to assess changes in leukocyte (CD11b/c, CD3, CD45R) and B cell subsets (CD45R, CD38, CD27, IgM) in renal allografts. The intra-graft distribution of leukocyte and B cell subsets was assessed by immunohistochemistry and immunofluorescence. Intra-graft transcription of chemokines and cytokines was analyzed by qPCR. Allograft fibrosis was stained using trichrome method. Functional parameters, including urinary protein excretion and serum creatinine concentration were measured by ELISA.

Results

Results: Simulation of non-adherence to immunosuppressive therapy led to development of dnDSA, predominantly of the complement-fixing IgG subclass IgG1 and IgG2b. Flow cytometric analysis of leukocyte populations showed a reduction in the absolute number of intra-graft leukocyte subsets (CD11b/c, CD3, CD45R) and specific B cell subsets (CD38, CD27, IgM) over time. Intra-graft mRNA expression of specific chemokines (lymphotoxin-ß) and IgG were increased over time. Functional and morphological changes indicating chronic allograft injury, such as fibrosis, proteinuria and serum creatinine were detected and increased over time in this model of non-adherence.

Conclusion

Conclusion: Using a rat model of non-adherence to immunosuppressive therapy in renal transplantation, we found an induction of dnDSA. Although intra-graft leukocyte and B cell numbers were reduced over time, a mild increase in functional and morphological indicators of chronic allograft injury was noted after non-adherence.

Funding

  • Private Foundation Support