Features of Epstein Barr Virus (EBV) reactivation after reduced intensity conditioning (RIC)

1. Features of Epstein Barr Virus (EBV) reactivation after reduced intensity conditioning (RIC) unrelated umbilical cord blood transplantation (UCBT) ZPeric,1,2 X Cahu, 1PChevallier,1 E Brissot, 1 T Guillaume,1 JDelaunay,1 S Ayari,1 VDubruille,1 SLe Gouill,1 B Mahe,1 T Gastinne,1 N Blin,1 BSaulquin,1NMilpied,1R Vrhovac,2JL Harousseau,1P Moreau,1 MCoste-Burel,3 BMImbert-Marcille,3 and M Mohty1 1 CHU de Nantes, Hematology Department, Nantes, France2 University Hospital, Hematology Department, Zagreb, Croatia3 CHU de Nantes, Laboratoire de virology, Nantes, France Introduction Results Discussion The absence of EBV-specific memory T cells in UCBgrafts, more frequent use of HLA-mismatched grafts, and use of ATG inducing in vivo T-cell depletion all contribute to a higherrisk of EBV-related complications in the subset of patients afterUCBT.(3) However, as we observed no increased risk of EBVcomplications in our group of patients, even when ATG used,other factors may modify the risk.Recent evidence-based guidelines from the European Conference on Infections in Leukemia recommended weekly screening of EBV-DNA for at least 3 months in high risk allo-HSCT recipients. In addition, other studies suggest that preemptive therapy with rituximab may be highly effective in controlling viral proliferation and avoiding progression into EBV-related LPD (4). In the current series, the response rate to pre-emptive rituximab appeared to be similar to that previously reported in the literature.(5) In rituximab-resistantpatients, options include chemotherapy regimens such as CHOP orEBV specific CTL lines generated using EBV-transformed lymphoblastoid B-cell lines. Patients' characteristics are summarized in Table 1. The median age was 50 (range, 18-66) years. 58% (n=19) of the patients had a myeloid malignancy, 36% (n=12) had a lymphoid malignancy and 6% (n=2) had severe aplastic anemia. 91% (n=30) of the patients received 2 CB units and 9% (n=3) received a single CB. Patients received a median of 4.0x107/kg (range, 2.2-5.8) total nucleated cells and a median of 0.9x105/kg (range, 0.2-3.7) CD34+ cells. Donors and recipients were mismatchedwith one mismatch in 43% of cases and 2 mismatches in 57%. A RIC including fludarabine (200 mg/m2 total dose), cyclophosphamide (50 mg/Kg) and low dose TBI (2 Gy.) was used in 29 cases (88%), while 8 patients (24%) who were not heavily pretreated before UCBT received ATG. Unrelated umbilical cord blood (UCB) isnow being increasingly used as an alternative stemcell source for allogeneic stem cell transplantation (allo-SCT). Because of the slow kinetics of immune reconstitution after UCBT, previous studies showed that EBV reactivation and EBV inducedlymphoprolipherative disease (LPD) may be of matter of concern.(1) However,more recent studies reported an infectious-relatedmortality (IRM) incidence similar to that of allo-SCT using HLA-matched unrelated donor. (2) This single centre study assessed incidence and predictive factors of EBV reactivation and LPD in 33 consecutive patients undergoing RIC UCBT. Engraftment occurred at a median of 12 (range, 8-60) days and 15% of patients developed grade 2-4 acute GVHD. The median follow-up for surviving patients was 468 (range, 92-1277) days. EBV reactivation was observed in 5 patients (15%) at a median of 132 (range, 85-438) days after UCBT. The cumulative incidence of EBV viremia is shown in Figure 1. Among the 5 patients experiencing EBV reactivation, 2 patients received ATG as part of their RIC. Four patients were treated with a median of 3 (range, 1-8) rituximab infusions. Two patients responded to rituximab, but 2 patients developed LPD. One of these 2 patients died before receiving any other anti-EBV therapy. In the other patient, LPD could be controlled after additional chemotherapy and 2 infusions of EBV specific cytotoxic T-lymphocytes. Of note, there was no significant difference in overall survival between patients with or without EBV reactivation (p=0.33). Patients and methods Table 1. Patients’ characteristics In all, 33 consecutive patients who received a RIC UCBT for hematological malignancies in a single institution (University Hospital of Nantes) between January 2005 and June 2009 were included in this retrospective study. During the first six months after allo-HSCT and in patients treated for GVHD, all patients were weekly DNA-PCR screened in the peripheral blood for EBV reactivation and were clinically monitored for clinical features attributable to EBV. EBV viremia was defined as 1000 copies of EBV DNA /105 cells. EBV LPD was defined as biopsy- or autopsy proven post-transplantation lymphoma, or viremia along with computerized tomography nodal or soft-tissue abnormalities consistent with LPD. Patients with EBV viremia >1000 copies on at least two consecutive occasions were treated with rituximab at a dose of 375 mg/m2 weekly until clearance of EBV viremia (usually for a maximum of 4 infusions). Figure 1. Cumulative incidence of EBV viremia post RIC allo-SCT Conclusions Overall, this study shows the rate of EBV reactivation after RIC UCBT to be relatively low (15%) and this is comparable to the incidence expected with PBSC or BM unrelated mismatched transplants. However, close EBV monitoring and the use of pre-emptive rituximab treatment appears to be mandatory since some cases may progress to LPD requiring additional interventions such as EBV-specific CTLs. Figure 2. Probability of Survival post RIC allo-SCT References Without EBV reactivation • Brunstein CGet al. Marked increased risk of Epstein-Barr virus relatedcomplications with the addition of antithymocyte globulin to a nonmyeloablative conditioning prior to unrelated umbilical cord blood transplantation. Blood 2006; 108(8):2874-2880. • 2. Parody Ret al. Severe infections after unrelated donor allogeneic hematopoietic stem cell transplantation in adults: comparison of cord blood transplantation with peripheral blood and bone marrow transplantation. Biol Blood Marrow Transplant. 2006;12:734-748 • 3. Clave Eet al. Epstein-Barrvirus (EBV) reactivation in allogeneic stem-celltransplantation: relationship between viral loadEBV-specific T-cell reconstitution and rituximabtherapy. Transplantation. 2004;77:76-84. • 4. Wagner HJet al. Prompt versus preemptive intervention for EBV lymphoproliferative • disease. Blood. 2004;103:3979-3981. • 5. Faye, A et al. Chimaeric anti-CD20 monoclonal antibody (rituximab) in post-transplant B- • lymphoproliferative disorder followingstem cell transplantation in children. BrJ Haematol • 2001; 115, 112–118. With EBV reactivation P = NS CONTACT: Zinaida Peric, MD; University Hospital Centre; Zagreb, Croatia zina_peric@yahoo.com