Abstract: FR-OR070
Increased Treg and Erythropoietin Levels in Kidney Transplant Recipients (KTR) with Erythrocytosis
Session Information
- Transplantation: Basic Science Innovations and Advances
November 07, 2025 | Location: Room 370A, Convention Center
Abstract Time: 05:30 PM - 05:40 PM
Category: Transplantation
- 2101 Transplantation: Basic
Authors
- Ajaimy, Maria, Montefiore Einstein Medical Center, New York, New York, United States
- Bigatti, Carolina, Icahn School of Medicine at Mount Sinai, New York, New York, United States
- Akalin, Enver, Montefiore Einstein Medical Center, New York, New York, United States
- Al Azzi, Yorg, Montefiore Einstein Medical Center, New York, New York, United States
- Korogodsky, Dana, Icahn School of Medicine at Mount Sinai, New York, New York, United States
- Cravedi, Paolo, Icahn School of Medicine at Mount Sinai, New York, New York, United States
Background
We previously showed that erythropoietin (EPO) prolongs allograft survival in mice by promoting regulatory T cell (Treg) induction in mice. In humans, the administration of recombinant EPO increases Treg. The effect of endogenous EPO in KTR on chronic immunosuppression is unknown. Post-transplant erythrocytosis (PTE) is defined as a persistently elevated hematocrit (HCT) associated with increased EPO levels. We hypothesized that KTR with PTE exhibit more circulating Tregs than non-PTE patients due to higher levels of endogenous EPO
Methods
we included KTR with PTE (HCT ≥50%) between 4/2024 and 2/2025. As controls, we included KTR without PTE (hematocrit <50%). We collected peripheral blood mononuclear cells, and we measured total CD4+,CD8+ Tcells,Tregs CD4 CD25 CD127, monocytes, and B cells (flow cytometry). We quantified production of intracellular cytokines :IL4, IL6 INFg, TNFa, IL17, TGFb, upon stimulation with PMA and ionomycin or LPS respectively for 3 hours. Plasma EPO levels were measured using the Human EPO ELISA Kit.Statistical significance was determined using an unpaired t-test
Results
Table 1 shows the baseline characteristics of the 2 groups. Patients with PTE had significantly higher serum EPO levels compared to controls (10.5 ± 5.9 vs 6.8 ± 2.5 mIU/mL, p = 0.02) and exhibited a significantly higher proportion of circulating Tregs compared to controls (p = 0.0096) (Figure 1). In addition the percentages of monocytes from PTE patients producing TNF-α and IL-6 were significantly lower levels compared to controls (p= 0.043 and p= 0.038, respectively). No difference was observed in other immune subsets analyzed
Conclusion
These findings suggest that, in KT recipients with PTE, high levels of endogenous EPO led to increased circulating Treg. This evidence could be leveraged to test the hypothesis that, in this patient population, lower levels of immunosuppression are needed to prevent rejection.