BackgroundThe prognostic significance of myelofibrosis (MF) grade in patients with myelodysplastic syndrome (MDS) following an allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains elusive.MethodsWe retrospectively analyzed data from 153 patients with MDS who underwent allo-HSCT and divided the patients into the MF-0/1 (N = 119) and MF-2/3 (N = 34) cohorts to explore the impact of MF on outcomes of allo-HSCT.ResultsThe 2-year rates of relapse, non-relapse mortality (NRM), overall survival (OS), and progression-free survival (PFS) were 10.9% (95% confidence interval [CI] 5.9%–17.7%), 16.3% (95% CI 10.2%–23.6%), 76.6% (95% CI 69.0%–85.1%), and 72.8% (95% CI 65.0%–81.5%) in the MF-0/1 cohort, and 16.9% (95% CI 5.8%–32.9%), 14.7% (95% CI 5.3%–28.7%), 71.8% (95% CI 57.6%–89.6%), and 68.4% (95% CI 53.6%–87.2%) in the MF-2/3 cohort, respectively. No significant difference in the outcomes of allo-HSCT was observed between the two cohorts. Both univariate and multivariate analyses confirmed that MF-2/3 in patients with MDS had no effect on the prognosis of transplantation. In addition, major/bidirectional ABO blood type between donors and recipients was an independent risk factor for OS (hazard ratio [HR], 2.55; 95% CI 1.25–5.21; P = 0.010) and PFS (HR, 2.21; 95% CI 1.10–4.42; P = 0.025) in the multivariate analysis. In the subgroup of patients diagnosed with MDS with increased blasts (MDS-IB), it was consistently demonstrated that the clinical outcomes of the MF-2/3 cohort were comparable with those of the MF-0/1 cohort. The risk factors for OS and PFS in patients with MDS-IB were non-complete remission at transplantation and major/bidirectional ABO blood type.ConclusionsIn conclusion, MF grade had no significant effect on prognosis of allo-HSCT in patients diagnosed with MDS. Major/bidirectional ABO blood type should be carefully considered in the context of more than one available donor.