Abstract
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%).
with the median of follow-up of 37.9 months, 78 patients died including 25 from TRM. Relapse was recorded in 70 patients. Seventy-two patients experienced acute GVHD (aGVHD) including 47 with II-IV grades and 30 with III-IV grades. In multivariate analyses, donor type (unrelated regardless the degree of HLA-matching vs related) and conditioning (nonmyeloablative vs myeloablative) were the most important risk factors negatively influencing the overall survival [p=.002; HR=2.038 and p=.016; HR=1.81, respectively) and event-free survival (p=.005; HR=1.783 and p=.015; HR=1.728, respectively). As expected, the only factor that influenced the risk of relapse was the conditioning type (nonmyeloablative vs myeloablative) (p=.048; HR=1.699) while donor type was found to influence TRM (p=.030; HR=2.428). Graft from unrelated one-antigen HLA-mismatched donor (9/10) was the foremost risk factor for acute grade II-IV GVHD (p=.019; HR=2.663; [95%CI: 1.178–6.019]).
In conclusion, except for acute II-IV GHVD, allo-CST from unrelated one-antigen HLA-mismatched donor (9/10), seemed to led to outcomes similar to those from HLA-identical unrelated donor (10/10) and may be considered as an alternative option for patients without a full-matched donor. Prospective studies are warranted, however, to confirm our data in larger cohort of patients.
No relevant conflicts of interest to declare.
Author notes
Asterisk with author names denotes non-ASH members.