51. Donor HLA mismatch promotes full donor T-cell chimerism in the allogeneic stem cell transplant with reduced-intensity conditioning and post-transplant cyclophosphamide GVHD prophylaxis.
- Author
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Cioccio J, Rakszawski K, Zheng H, Nickolich M, Naik S, Wirk B, Rybka W, Ehmann C, Silar B, Vajdic C, Shah N, Tuanquin L, Greiner R, Brown V, Hohl R, Claxton D, Mineishi S, Minagawa K, and Shike H
- Subjects
- Humans, Chimerism, T-Lymphocytes, Cyclophosphamide therapeutic use, Stem Cell Transplantation adverse effects, HLA Antigens, Transplantation Conditioning adverse effects, Unrelated Donors, Retrospective Studies, Hematopoietic Stem Cell Transplantation adverse effects, Graft vs Host Disease etiology
- Abstract
Full donor T-cell chimerism (FDTCC) after allogeneic stem cell transplant (allo-SCT) has been associated with improved outcomes in hematologic malignancy. We studied if donor human leukocyte antigen (HLA) mismatch improves achievement of FDTCC because mismatched HLA promotes donor T-cell proliferation where recipient T-cells had been impaired by previous treatment. Patients (N = 138) received allo-SCT with reduced-intensity conditioning (RIC) from 39 HLA mismatched donors (16 unrelated; 23 haploidentical) with post-transplant cyclophosphamide (PTCy) or 99 matched donors (21 siblings; 78 unrelated) with PTCy (N = 18) or non-PTCy (N = 81). Achievement of FDTCC by day 100 was higher with HLA mismatched donors than matched donors (82.1% vs. 27.3%, p < 00,001), which was further improved with 200 cGy total body irradiation (87.9%) or lymphoid (versus myeloid) malignancy (93.8%). Since all mismatched transplants used PTCy, FDTCC was higher with PTCy than non-PTCy (68.4% vs. 25.7%, p < 0.00001), but not in the matched transplant with PTCy (38.9%), negating PTCy as the primary driver. Lymphocyte recovery was delayed with PTCy than without (median on day + 30: 100 vs. 630/µL, p < 0.0001). The benefit of FDTCC was not translated into survival outcomes, especially in myeloid malignancies, possibly due to the insufficient graft-versus-tumor effects from the delayed lymphocyte recovery. Further studies are necessary to improve lymphocyte count recovery in PTCy transplants., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2023
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