Impact of Serum EBV-qPCR Positivity on the Outcome of Allogeneic Stem Cell Transplantation: A Retrospective Study of 406 Patients.
Authors: Juvonen Eeva , Aalto Sanna , Volin Liisa , Hedman Klaus , Ruutu Tapani 
Published: April 2020

Abstract
The course of serum EBV-PCR positivity and its impact on the outcome of allogeneic stem cell transplantation (Tx) has not been known well until recently. We have studied retrospectively with quantitative real-time EBV-PCR (qPCR) 5445 serum samples (median 14 sera/patient, range 1–26) collected and frozen-stored according to a predefined schedule within 2 years after Tx from 406 consecutive allogeneic patients transplanted in 1988–1999. 398 patients had a malignant hematological disease, 8 had aplastic anemia. Of the donors 310 were sibling and 96 were unrelated. All donors were HLA A, B, DR matched. 374 grafts were bone marrow and 32 blood stem cells. The grafts were unmanipulated. Patients with an unrelated donor were given anti-thymocyte globulin (ATG). GVHD prophylaxis consisted of cyclosporin A and methotrexate, and in addition methylprednisolone (MP) in 270 patients. Second line treatment for MP-refractory GVHD was ATG. EBV-qPCR positivity (&gt;500 copies/ml) occurred in 55 patients (13.5 %). The median time from the Tx to the first positive sample was 64 days (range day 10 pretransplant - day 537). In 13 patients EBV-qPCR positivity appeared after day 100 post Tx. In 17 patients the EBV-qPCR positivity converted back to negativity, in 25 patients the copy numbers progressively increased or the count was high in the first positive sample, and in 13 patients a positive EBV-qPCR with a low copy number was seen in the last available sample. Only 2 patients with post-transplant lymphoproliferative disorder (PTLD) received EBV-targeted treatment. 7 /55 (13 %) patients with positive EBV-qPCR were alive with a median survival of 3.6 (range 0.7–171) months, while 180 /351 (51%) EBV-qPCR negative patients were alive with a median survival of 51 (0.1–189) months (p&lt;0.0001). In the EBV-qPCR positive group the main cause of death was GVHD in 26 patients, 9 patients relapsed, 6 patients died of infection, and 1 patient had VOD. In 6 patients the cause of death was PTLD. In addition, confirmed PTLD was diagnosed in 6 other patients (3 with GVHD, 2 with relapse and 1 with fungal infection). The cumulative survival was statistically significantly better in those with first positive serum after day 100 post Tx (0.31 vs 0.07, p&lt;0.0001, Log Rank). In the EBV-qPCR negative group the cause of death was GVHD in 46, relapse in 84, infection in 21, other transplant related mortality in 17 patients, and other cause in 3 patients. 1 relapsed patient had also PTLD, and two patients with myeloid leukemia died of NHL. In univariant analysis significant risk factors for EBV-qPCR positivity were unrelated donor, acute GVHD, MP ≥ 2mg/kg/day, and the use of ATG (p&lt;0.0001 each, Chi-Square). Positive EBV-qPCR decreased significantly also the survival of the patients without any of the given risk factor. When compared with the EBV-qPCR neg patients, the survival of EBV-qPCR+ patients with no acute GVHD (alive 6/21 vs 123/216, p= 0.02 Chi-Square), with no ATG given (3/12 vs 146/260, p = 0.04), or without the use of MP ≥ 2mg/kg/day (4/18 vs 125/211 p=0.003) was inferior.
Conclusions: In allogeneic transplant patients the EBV-qPCR positivity had a negative impact on the outcome of the transplantation.