Clinicopathological Study Of 12 Cases Of EBV-Associated Post-Transplant Lymphoproliferative Disorder (PTLD) After Allogeneic SCT: A Single Institution Analysis Of 825 Transplants Including 572 Cord Blood Transplants In Toranomon Hospital
Authors: Kaji Daisuke , Ota Yasunori , Nishida Aya , Yamamoto Hisashi , Ota Hikari , Ishiwata Kazuya , Tsuji Masanori , Yamamoto Go , Asano-Mori Yuki , Uchida Naoyuki , Wake Atsushi , Izutsu Koji , Taniguchi Shuichi 
Published: October 2019

Abstract

Background
EBV-associated post-transplant lymphoproliferative disorder (EBV-PTLD) is uncommon but one of serious complications after allogeneic stem cell transplantation (SCT). However, there has been little literature published on clinicopathological feature of it.

Method
We retrospectively investigated 825 cases of allogeneic SCT (unrelated bone marrow (uBM) 159, related peripheral blood (rPB) 94, cord blood (CB) 572) at Toranomon Hospital between January 2006 to November 2012. EBV-PTLD was defined as histologically confirmed Epstein-Barr virus (EBV) positive lymphoproliferative disorder developed after allogeneic SCT.

Results
We identified 12 cases of EBV-PTLD in our cohort. Cumulative incidence of EBV-PTLD at 2 years was 1.5%. Median time from allogeneic SCT to the diagnosis of EBV-PTLD was 6.4 (2.5-26) months. Eight patients were male and median age at the diagnosis of EBV-PTLD was 58.5 years (28-66). Underlying diseases were acute myeloid leukemia (n=5), myelodysplastic syndrome (1), acute lymphoblastic leukemia (2), adult T cell leukemia-lymphoma (1), aplastic anemia (2) and chronic myeloid leukemia in blastic phase (1). Conditioning regimens were fludarabine-based (n=10) and TBI/CY (n=2). None had an antithymocyte globulin-containing regimen. Donor sources were uBM (n=1) and CB (11). EBV serology before allogeneic SCT was tested in 11 and all were positive. Patients who received CB showed higher incidence of EBV-PTLD compared to those in non-CB cohort (2.2% vs 0.6%, p < 0.01), although patients characteristics was different between them. One patient developed PTLD after third allogeneic SCT. All but one patients had a history of acute graft-versus-host disease (aGVHD) of grade I (n=2), grade II (6) and grade III (3), respectively. Chronic GVHD was observed in 6 patients. Eight patients were on immunosuppressive therapy (IST) with calcineurin inhibitors and/or steroids when EBV-PTLD was suspected for the first time. Although lymphadenopathy was detected by CT scan in 7 patients, surface lymph nodes were swollen in only 3 patients. Initial manifestations were fever in 8, and diarrhea in 5 patients. EBV-PTLD was diagnosed from lymph nodes (n=3), skin (3), bone marrow (2), stomach/duodenum (1), colon (2), and lung (1), respectively. Histological feature was monomorphic (n=4), polymorphic (2), early lesion (4), and unknown (2), respectively. LMP1 and EBNA2 was positive in 40% (4/10) and 30% (3/10), suggesting latency status of I in 50% (6/12), II in 8.3% (1/12), III in 25% (3/12), and unknown in 16.7% (2/12). EBV DNA of 100 copies/microL or above was detected in peripheral blood in all of the EBV-PTLD cases. The treatment for EBV-PTLD were rituximab alone (n=3), rituximab plus reduction of IST (6), rituximab plus cytotoxic chemotherapy (1), and observation alone(2). Although 8 patients achieved response, 2 patients suffered a relapse of EBV-PTLD. With a median follow up of 27.5 (4.1-47.7) months, 2-year overall survival was 46.9% after diagnosis of EBV-PTLD. Eight patients died and 4 are alive without relapse of EBV-PTLD. Causes of death were EBV-PTLD (n=2), relapse of underlying disease(3), infectious disease(2), and aGVHD(1).

Conclusion
Twelve cases of EBV-PTLD were identified in 825 transplants. Cumulative incidence of EBV-PTLD at 2 years was 1.5%. The incidence of EBV-PTLD after CB transplant was higher than that after non CB transplant, although we have to take into consideration that patients feature was different between them. Response to rituximab and/or reduction of IST was observed in 8 patients with a 2-year overall survival rate of 46.9%. Patients with prior aGVHD and with longer duration of immunosuppressive therapy may have an increased risk of developing EBV-PTLD. Since the initial manifestations were often equivocal, and survival rate after diagnosis is not high, having EBV-PTLD in mind as one of the possibilities is critical for prompt diagnosis.

Disclosures:
No relevant conflicts of interest to declare.