Allogeneic Stem Cell Transplantation From Unrelated One-Antigen HLA-Mismatched Donor, Increases Acute II-IV Gvhd Incidence without Interfering with Other Post-Transplant Complications

Abstract 2378

Allogeneic stem cell transplantation (allo-SCT) offers potential curative treatment of for a wide range of otherwise fatal hematological diseases. However, only one third of patients have an HLA-identical sibling donor. We have previously reported that in patients with standard risk malignancy, transplantation from unrelated HLA-allellically matched donors (10/10) led to outcomes similar to those from HLA-identical sibling donors (Yakoub-Agha et al, JCO 2006). Indeed, with the increase in the number of single-child families, stem cell grafts from unrelated donors are being increasingly used and more than 30% of patients eligible for allo-CST, are still lacking a well-matched donor. In the attempt to investigate the impact of unrelated one-antigen HLA-mismatched graft, we report a single center retrospective study on 209 patients who underwent allo-CST from identical HLA-sibling donor (n=123), unrelated HLA-matched donor (10/10) (n=73) and unrelated one-antigen-HLA-mismatched donor (9/10) (n=13) over the last 5 years. In order to homogenize our cohort, patients with CML, aplastic anemia or lymphoproliferative disorder were excluded from the study. Therefore, underlying diseases were AML (n=104), ALL (n=54), myelodysplastic syndrome (n=30), and myeloproliferative syndrome (n=21). Of the 117 (56%) males patients, 49 (23%) received graft from female donor (classical sex-mismatch). Medians age of recipients and donors at transplantation were 45.2 years (4.4-65.5) and 40.8 years (2.0-67.5), respectively. Patients received conditioning regimens using either myeloablative (n=149) including 81 who received High-dose TBI (12Gy) or nonmyeloablative (n=60) including 48 who received low-dose TBI (2Gy). Antithymoglobulin was given to 25 pts. Bone marrow was the main source of stem cells (n=150; 72%).