Session Name: Tolerance: Clinical Studies
Session Date & Time: None. Available on demand.
*Purpose: Simultaneous transplantation of a solid organ and bone marrow from an identical donor is a possible means of achieving transplant tolerance. Here, we attempted to identify biomarkers that indicate transplant tolerance for discontinuation of immunosuppressants in combined kidney and bone marrow transplantation (CKBMT).
*Methods: We compared various immunological parameters that evaluate the transplant tolerance status between conventional kidney transplanted (KT) recipients (n = 20) and CKBMT recipients (n = 6) by using flow cytometry. To measure the anti-donor responses, mixed lymphocyte reaction (MLR) assays were performed with responder peripheral blood mononuclear cells (PBMCs) of CKBMT recipients and stimulator PBMCs of autologous, donor, and third party.
*Results: Among six CKBMT recipients, three successfully discontinued immunosuppressants (tolerant group) and three could not (non-tolerant group). The CD45RA–FoxP3hi activated regulatory T (Treg) cell subpopulation was expanded in CKBMT recipients compared to conventional kidney transplant patients, and this was more obvious in the tolerant group than the non-tolerant group. The ratio of CD45RA–FoxP3hi activated Treg cells to CD45RA–FoxP3lo non-suppressive cells showed good discrimination between the tolerant and non-tolerant groups.
*Conclusions: Thus, our findings propose a biomarker that can distinguish CKBMT patients who achieve transplant tolerance and are eligible for discontinuation of immunosuppressants and may provide insight into tolerance mechanisms in CKBMT.
To cite this abstract in AMA style:Kwon Y, Lee K, Park J. Expansion of Cd45ra-foxp3hi Activated Regulatory T Cells Predict Immune Tolerance in Patients with Combined Kidney and Bone Marrow Transplantation [abstract]. Am J Transplant. 2021; 21 (suppl 3). https://atcmeetingabstracts.com/abstract/expansion-of-cd45ra-foxp3hi-activated-regulatory-t-cells-predict-immune-tolerance-in-patients-with-combined-kidney-and-bone-marrow-transplantation/. Accessed June 18, 2021.
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