Superior immune reconstitution using Treg-expanded donor cells versus PTCy treatment in preclinical HSCT models
Dietlinde Wolf, … , Krishna V. Komanduri, Robert B. Levy
Dietlinde Wolf, … , Krishna V. Komanduri, Robert B. Levy
Published October 18, 2018
Citation Information: JCI Insight. 2018;3(20):e121717. https://doi.org/10.1172/jci.insight.121717.
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Research Article Immunology Transplantation

Superior immune reconstitution using Treg-expanded donor cells versus PTCy treatment in preclinical HSCT models

Abstract

Posttransplant cyclophosphamide (PTCy) has been found to be effective in ameliorating acute graft-versus-host disease (GVHD) in patients following allogeneic hematopoietic stem cell transplantation (aHSCT). Adoptive transfer of high numbers of donor Tregs in experimental aHSCT has shown promise as a therapeutic modality for GVHD regulation. We recently described a strategy for in vivo Treg expansion targeting two receptors: TNFRSF25 and CD25. To date, there have been no direct comparisons between the use of PTCy and Tregs regarding outcome and immune reconstitution within identical groups of transplanted mice. Here, we assessed these two strategies and found both decreased clinical GVHD and improved survival long term. However, recipients transplanted with Treg-expanded donor cells (TrED) exhibited less weight loss early after HSCT. Additionally, TrED recipients demonstrated less thymic damage, significantly more recent thymic emigrants, and more rapid lymphoid engraftment. Three months after HSCT, PTCy-treated and TrED recipients showed tolerance to F1 skin allografts and comparable immune function. Overall, TrED was found superior to PTCy with regard to weight loss early after transplant and initial lymphoid engraftment. Based on these findings, we speculate that morbidity and mortality after transplant could be diminished following TrED transplant into aHSCT recipients, and, therefore, that TrED could provide a promising clinical strategy for GVHD prophylaxis.

Authors

Dietlinde Wolf, Cameron S. Bader, Henry Barreras, Sabrina Copsel, Brent J. Pfeiffer, Casey O. Lightbourn, Norman H. Altman, Krishna V. Komanduri, Robert B. Levy

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Figure 1

Treg-expanded donor cells show advantages over PTCy treatment early after transplant; however, long-term outcomes are comparable in a major MHC-mismatch model of preclinical HSCT.

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Treg-expanded donor cells show advantages over PTCy treatment early afte...
(A–C) A HSCT utilizing a B6 BALB/c donor/recipient mouse model involving a complete MHC mismatch was performed on day 0. Lethally irradiated (8.5-Gy) BALB/c mice received 5 × 106 TCD B6-CD45.1 BM cells and spleen cells from expanded (TL1A-Ig/IL-2; Treg-expanded donor cells [TrED] group) or untreated B6-FoxP3rfp (GVHD and PTCy group) donor mice adjusted to contain 1.1 × 106 total T cells. Cyclophosphamide was given on day 3 and 4 after HSCT at 80 mg/kg i.p. Weights (day 12–19) (A), clinical scores (day 12–19) (B), and survival (P = ns) (C) (n = 10–12). Statistical analysis for weights and clinical score was also performed to assess the overall model using JMP 13 Pro. No statistical significance between PTCy and TrED was detected. A log-rank test was used for survival analysis. (D) Donor Treg frequencies and cell numbers in spleens on day 21 after HSCT are significantly higher in TrED recipients compared with PTCy-treated and GVHD control animals (n = 4). Data are expressed as mean ± SEM and were analyzed by ANOVA with Bonferroni correction for multiple comparisons. Data are pooled from 2 independent experiments. (E) Treg frequencies and cell numbers in lamina propria on day 21 after HSCT are significantly higher in TrED recipients compared with PTCy-treated and GVHD control animals (n = 3). Data are expressed as mean ± SEM and were analyzed by ANOVA with Bonferroni correction for multiple comparisons. Data shown are from 1 experiment. (F) Representative H&E-stained sections from colons on day 21 after HSCT show severe colitis in tissue from untreated HSCT recipients, with disruption of architecture, acute inflammation with severe lymphocyte infiltration, edema, mucosal thickening, and severe necrosis. In contrast, PTC colonic tissue showed mild hyperplasia, mild inflammation, and edema in the submucosa. Finally, colon tissue from TrED recipients exhibited patchy and mild colitis without hyperplasia or necrosis. Original magnification, ×200. Pathology scores are shown on the right (n = 3–6). Data (from 2 independent experiments) are shown as mean ± SEM; ANOVA with Bonferroni correction was applied for multiple comparisons. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001. Scale bars: 100 μm.