Janus kinase 2 (JAK2) signal transduction is a critical mediator of the immune response. JAK2 is implicated in the onset of graft-versus-host disease (GVHD), which is a significant cause of transplant-related mortality after allogeneic hematopoietic cell transplantation (allo-HCT). Transfer of JAK2−/− donor T cells to allogeneic recipients leads to attenuated GVHD yet maintains graft-versus-leukemia. Th1 differentiation among JAK2−/− T cells is significantly decreased compared with wild-type controls. Conversely, iTreg and Th2 polarization is significantly increased among JAK2−/− T cells. Pacritinib is a multikinase inhibitor with potent activity against JAK2. Pacritinib significantly reduces GVHD and xenogeneic skin graft rejection in distinct rodent models and maintains donor antitumor immunity. Moreover, pacritinib spares iTregs and polarizes Th2 responses as observed among JAK2−/− T cells. Collectively, these data clearly identify JAK2 as a therapeutic target to control donor alloreactivity and promote iTreg responses after allo-HCT or solid organ transplantation. As such, a phase I/II acute GVHD prevention trial combining pacritinib with standard immune suppression after allo-HCT is actively being investigated (https://clinicaltrials.gov/ct2/show/NCT02891603).
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Feb 13 2018|
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. The Flow Cytometry, University of South Florida (USF) Comparative Medicine and Vivarium, Analytic Microscopy, and Tissue Cores at Moffitt/USF were utilized in completing this work. The core facilities are supported partially by the Moffitt Cancer Center Support Grant P30-CA076292. This work was supported by Grants R01 CA143812 and CA169116 (to X.-Z.Y.) and Grants K08 HL11654701A1 and R01 HL133823 (to B.C.B.) from the National Institutes of Health.
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- Graft rejection