[Comparison of EB virus infection between short term and long term use of mycophenolate mofetil for prophylaxis of graft versus host disease after haploidentical hematopoietic stem cell transplantation].

To investigate the role of short-term use of mycophenolate mofetil (MMF) in EB viral infection and acute graft-versus host disease (GVHD) in patients receiving haploidentical hematopoietic stem cell transplantation (haplo-HSCT) . Adult patients (≥14 years) who were diagnosed with hematological malignancies received haplo-HSCT in Peking University Institute of Hematology from May 2016 to December 2017 were retrospectively reviewed. The median age was 30 (14-60) years old. A total of 498 patients including 277 males and 221 females were enrolled. Donors' median age was 38 (8-66) years old. All patients were classified into long-term use of MMF (=199), which was defined as 500 mg every 12 hours from day 9 pre-transplant to 250 mg every 12 hours from day 30 after transplant then withdrawal on day 45 to 60 after transplant, and short-term use of MMF (=299), which was defined as 500 mg every 12 hour from day 9 pre-transplant then withdrawal till neutrophil engraftment. Kaplan-Meier model was used to analyze the cumulative incidence of EBV infection, and the Cox proportional regression model for multivariate analysis. Characteristics including sex, age, disease types, mismatched HLA loci, donor-recipient relationship, donor-recipient blood type, donor age, and donor sex were comparable between two groups (all ＞0.05). According to once, the incidence of EBV viremia, defined as EBV＞10 copies/ml at least once, in short-term group and long-term group was 19.4% (58/299) and 27.6% (55/199) respectively (=0.046).Donor age and the duration of MMF prophylaxis (short-term group as reference) were associated with EBV viremia according to multivariate analysis [=1.022(95% 1.006-1.038),1.600(95% 1.059-2.418);=0.006 and 0.026, respectively]. The incidence of grade Ⅱ-Ⅳ and Ⅲ/Ⅳ acute GVHD in long-term and short-term group was 32.2% (64/199) versus 20.7% (62/299)(=0.005) and 10.1% (20/199) versus 8.0% (24/299) (=0.427), respectively. Donor sex (female as reference) and duration of MMF prophylaxis (short-term group as reference) were associated with grade Ⅱ-Ⅳ acute GVHD [=1.908(95% 1.079-3.373),1.752(95% 1.161-2.643);=0.026 and 0.008, respectively].There were no statistical differences in the incidence of CMV viremia, refractory CMV viremia and hemorrhagic cystitis (all ＞0.05) between the two groups. Short-term use of MMF can reduce EBV viremia without increasing the development of acute GVHD in haplo-HSCT patients.