Posttransplantation cyclophosphamide prevents graft-versus-host disease by inducing alloreactive T cell dysfunction and suppression

Autor: Michael Eckhaus, Lucas P. Wachsmuth, Christopher G. Kanakry, David Venzon, Ronald E. Gress, Michael T. Patterson
Rok vydání: 2019
Předmět:
Zdroj: Journal of Clinical Investigation. 129:2357-2373
ISSN: 1558-8238
0021-9738
Popis: Post-transplantation cyclophosphamide (PTCy) recently has had a marked impact on human allogeneic hematopoietic cell transplantation (HCT). Yet, our understanding of how PTCy prevents graft-versus-host disease (GVHD) largely has been extrapolated from major histocompatibility complex (MHC)-matched murine skin allografting models that were highly contextual in their efficacy. Herein, we developed a T-cell-replete, MHC-haploidentical, murine HCT model (B6C3F1→B6D2F1) to test the putative underlying mechanisms: alloreactive T-cell elimination, alloreactive T-cell intrathymic clonal deletion, and suppressor T-cell induction. In this model and confirmed in four others, PTCy did not eliminate alloreactive T cells identified using either specific Vβs or the 2C or 4C T-cell receptors. Furthermore, the thymus was not necessary for PTCy's efficacy. Rather, PTCy induced alloreactive T-cell functional impairment which was supported by highly active suppressive mechanisms established within one day after PTCy that were sufficient to prevent new donor T cells from causing GVHD. These suppressive mechanisms included the rapid, preferential recovery of CD4+CD25+Foxp3+ regulatory T cells, including those that were alloantigen-specific, which served an increasingly critical function over time. Our results prompt a paradigm-shift in our mechanistic understanding of PTCy. These results have direct clinical implications for understanding tolerance induction and for rationally developing novel strategies to improve patient outcomes.
Databáze: OpenAIRE
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