Biological Research (Jan 2015)

CD4+ T cells in aged or thymectomized recipients of allogeneic stem cell transplantations

  • Hiroshi Takahashi,
  • Kazuhiko Ikeda,
  • Kazuei Ogawa,
  • Syunnichi Saito,
  • Alain M Ngoma,
  • Yumiko Mashimo,
  • Koki Ueda,
  • Miki Furukawa,
  • Akiko Shichishima-Nakamura,
  • Hiroshi Ohkawara,
  • Kenneth E Nollet,
  • Hitoshi Ohto,
  • Yasuchika Takeishi

DOI
https://doi.org/10.1186/S40659-015-0033-8
Journal volume & issue
Vol. 48, no. 0
pp. 1 – 8

Abstract

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BACKGROUND: CD4+CD25highFOXP3+ regulatory T (Treg) cells, which include thymus-derived and peripherally induced cells, play a central role in immune regulation, and are therefore crucial to prevent graft-versus-host disease (GVHD). The increasing use of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for elderly patients with thymus regression, and our case of allo-HSCT shortly after total thymectomy, raised questions about the activity of thymus-derived Treg cells and peripherally induced Treg cells, which are otherwise indistinguishable. RESULTS: We found that despite pre-transplant thymectomy or older age, both naïve and effector Treg cells, as well as naïve and effector conventional T cells, proliferated in allo-HSCT recipients. Higher proportions of total Treg cells 1 month post allo-HSCT, and naïve Treg cells 1 year post allo-HSCT, appeared in patients achieving complete chimera without developing significant chronic GVHD, including our thymectomized patient, compared with patients who developed chronic GVHD. CONCLUSIONS: Treg cells that modulate human allogeneic immunity may arise peripherally as well as in the thymus of allo-HSCT recipients.

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