Inconsistent results have been reported regarding the influence of graft composition on the incidence of graft versus host disease (GVHD), disease control and survival after reduced-intensity conditioning (RIC) allogeneic peripheral blood stem cell transplantation (allo-PBSCT). These discrepancies may be at least in part explained by the differences in disease categories, disease status at transplant, donor type and conditioning. The current retrospective EBMT registry study aimed to analyze the impact of CD3+ and CD34+ cells dose on the outcome of RIC allo-PBSCT in patients with acute myelogenous leukemia (AML) in first complete remission, allografted from HLA-matched unrelated donors (10 of 10 match). We included 203 adults. In univariate analysis, patients transplanted with the highest CD3+ and CD34+ doses (above the third quartile cut-off point values, >347 × 10^6/kg and >8.25 × 10^6 /kg, respectively) had an increased incidence of grade III-IV acute (a) GVHD (20% vs. 6%, P = .003 and 18% vs. 7%, P = .02, respectively). There was no association between cellular composition of grafts and transplant-related mortality, AML relapse, incidence of chronic GVHD and survival. Neither engraftment itself nor the kinetics of engraftment were affected by the cell dose. In multivariate analysis, CD3+ and CD34+ doses were the only adverse predicting factors for grade III-IV aGVHD (HR = 3.6; 95%CI: 1.45-9.96, P = .006 and 2.65 (1.07-6.57), P = .04, respectively). These results suggest that careful assessing the CD3+ and CD34+ graft content and tailoring the cell dose infused may help in reducing severe acute GVHD risk without negative impact on the other transplantation outcomes.

This retrospective study by the European Society for Blood and Marrow Transplantation analyzed the outcome of 2224 patients with myelofibrosis (MF) who underwent allogeneic stem cell transplantation (allo-SCT) between 2000 and 2014; 781 (35%) underwent myeloablative conditioning (MAC) and 1443 (65%) reduced-intensity conditioning (RIC). Median patient age was 52.9 years (range, 18 to 74 years) and 57.5 years (range, 21 to 76 years) in the MAC and RIC cohorts, respectively. Donor type was similar: matched sibling donors (MAC, 317 [41%]; RIC, 552 [38%]) and unrelated donors (MAC, 464 [59%]; RIC, 891 [62%]). Median time to both neutrophil and platelet (>20 £ 10 9 /L) engraftment did not differ between cohorts. Rates of grade II to IV acute GVHD were 28% (MAC) and 31% (RIC; P = NS).

The role of spleen size and splenectomy for the prediction of post‐allogeneic hematopoietic stem cell transplant (allo‐HCT) outcome in myelofibrosis remains under debate. In EBMT registry, we identified a cohort of 1195 myelofibrosis patients transplanted between 2000‐2017 after either fludarabine‐busulfan or fludarabine‐melphalan regimens. Overall, splenectomy was performed in 202 (16.9%) patients and its use decreased over time (28.3% in 2000‐2009 vs 14.1% in 2010‐2017 period). By multivariate analysis, splenectomy was associated with less NRM (HR 0.64, 95% CI 0.44‐0.93, P = .018) but increased risk of relapse (HR 1.43, 95% CI 1.01‐2.02, P = .042), with no significant impact on OS (HR 0.86, 95% CI 0.67‐1.12, P = .274). However, in subset analysis comparing the impact of splenectomy vs specific spleen sizes, for patients with progressive disease, an improved survival was seen in splenectomised subjects compared to those patients with a palpable spleen length ≥ 15 cm (HR 0.44, 95% CI 0.28‐0.69, P < .001), caused by a significant reduction in NRM (HR 0.26, 95% CI 0.14‐0.49, P < .001), without significantly increased relapse risk (HR 1.47, 95% CI 0.87‐2.49, P = .147). Overall, despite the possible biases typical of retrospective cohorts, this study highlights the potential detrimental effect of massive splenomegaly in transplant outcome and supports the role of splenectomy for myelofibrosis patients with progressive disease and large splenomegaly.

Allogeneic Haematopoietic Cell Transplantation (allo-HCT) remains the only curative approach in Myelofibrosis (MF). Despite advances over recent decades, relapse and non-relapse mortality rates remain significant. Relapse rates vary between 15% and 25% across retrospective studies and management strategies vary widely, ranging from palliation to adoptive immunotherapy and, in some cases, a second allo-HCT. Moreover, in allo-HCT, there is a higher incidence of poor graft function and graft failure due to splenomegaly and a hostile 'pro-inflammatory' marrow niche. The Practice Harmonisation and Guidelines subcommittee of the Chronic Malignancies Working Party (CMWP) of EBMT convened an international panel consisting of transplant haematologists, histopathologists and molecular biologists to propose practical, clinically relevant definitions of graft failure, poor graft function and relapse as well as management strategies following allo-HCT. A systematic approach to molecular monitoring, histopathological assessment and chimerism testing is proposed. These proposed recommendations aim to increase the accuracy and uniformity of reporting and to thereby facilitate the development of more consistent approaches to these challenging issues. In addition, we propose management strategies for these complications.

The role of autologous hematopoietic SCT (autoHSCT) in the treatment of high-risk (HR) adult ALL is controversial. In this study, we retrospectively analyzed the results of autoHSCT according to the status of minimal residual disease (MRD) at transplantation, as a joint analysis of the European Study Group for Adult ALL (EWALL). Data on 123 recipients of autoHSCT, aged 31 (16-59) years, with B-lineage (n=77) or T-lineage (n=46) ALL were included. In a cohort of Ph-negative ALL, the probability of leukemia-free survival at 5 years was higher for patients with MRD <0.1% compared with those with MRD > or = 0.1% (57 vs 17%, P=0.0002). The difference was significant for T-lineage ALL (62 vs 8%, P=0.001), and a tendency was observed for B-lineage ALL (54 vs 26%, P=0.17). In a multivariate analysis, adjusted for other potential prognostic factors, high MRD level remained the only independent factor associated with increased risk of failure (risk ratio, 2.8; P=0.0005). We conclude that MRD determines the outcome of autoHSCT in HR adult ALL. Our results suggest the need to reevaluate the role of this treatment option in prospective trials.