The Outcomes of Systemic Chronic Active EBV Infection Treatment By Allogeneic Hematopoietic Stem Cell Transplantation: An Analysis of Japanese Registry Data
Authors: Arai Ayako , Yamamoto Masahide , Sato Maho , Onishi Yasushi , Sasahara Yoji , Sano Hideki , Masuko Masayoshi , Nakamae Hirohisa , Matsuoka Ken-Ichi , Ara Takahide , Washio Kana , Onizuka Makoto , Watanabe Kenichiro , Hirakawa Tsuneaki , Nishio Miwako , Sakashita Chizuko , Kobayashi Tohru , Sawada Akihisa , Ichinohe Tatsuo , Fukuda Takahiro , Hashii Yoshiko , Atsuta Yoshiko 
Published: November 2021

Abstract
Background and aims
Systemic chronic active Epstein-Barr virus infection (sCAEBV) is classified as T- or NK-cell neoplasms in the WHO classification revised in 2017. Although allogeneic stem cell transplantation (allo-HSCT) is efficacious for sCAEBV, the effects are yet to be analyzed in a large number of cases due to the disease rarity. To investigate the outcomes and the prognostic factors of allo-HSCT in sCAEBV under the definition of the WHO 2017 classification, we analyzed retrospectively using the database of Japanese Society for Transplantation and Cellular Therapy (JSTCT).

Methods
Data collection
We used the clinical data of hematopoietic stem cell transplantation (HSCT) recipients of the Transplant Registry Unified Management Program (TRUMP) sponsored by JSTCT and Japanese Data Center for Hematopoietic Cell Transplantation (JDCHCT). Patients who underwent HSCT to cure EBV-associated diseases, secondary hemophagocytic lymphohistiocytosis (HLH), and virus-associated hemophagocytic syndrome between January 1993 and December 2016 were selected in TRUMP database, and on our behalf, JDCHCT sent out survey questions to the institutions of these patients to collect additional data to check if the diagnosis of sCAEBV matches our criteria, to analyze disease status at the time of HSCT, and to evaluate the efficacy of different treatment methods.
The diagnosis of sCAEBV
sCAEBV was diagnosed according to criteria suggested in 2016 by the Research group of Measures against Intractable Diseases by Ministry of Health, Labour and Welfare of Japan: (1) elevated EBV DNA load in peripheral blood (PB) (&gt; 10 2.5 copies/μg DNA), (2) detection of EBV infection in T or NK cells from the affected tissues or PB, (3) systemic inflammatory symptoms such as fever, lymphadenopathy, liver dysfunction, progressive skin lesions, vasculitis, and uveitis persisting for &gt; 3 months, and (4) exclusion of other possible diseases, such as primary EBV infection, autoimmune disease, immunodeficiencies, and lymphomas. Patients who fulfilled all (1) to (4) were diagnosed as sCAEBV. These criteria are compatible with the definition of sCAEBV described in the WHO definition of 2017.
The definitions of disease activities and responses
The disease activities are defined in previous reports (Blood. 2012;119, p673 and BMT. 2016;51, p879) as follows: positive of fever, ALT level elevation, vasculitis, progressive skin lesions, or uveitis. We defined the complete resolution of disease activity as complete response (CR) and CR with a significant decrease in PB EBV-DNA load (&lt; 10 2.5 copies/μg DNA) as virological CR (vCR).

Results
81 patients who met the diagnostic criteria of sCAEBV were analyzed. The median age at HSCT was 24 years old, and the three-year overall survival rate (3-year OS) was 74.0%. Of 74 patients whose viral load after HSCT evaluated, 49 (66.2%) achieved vCR. The multivariate cox proportional hazard model revealed that advanced age, adolescent and young adult (AYA) (age, 15-39; n = 48) and adult (age, &gt; 40; n = 13), was a risk factor of poor OS. The hazard ratios (HR) of AYA and adult groups were 10.14 and 4.63 respectively. It also showed that the presence of HLH at HSCT (HR 4.55), high sIL-2R (≥ median, 691 U/mL) at HSCT (HR 5.27), and conditioning without total body irradiation (HR 3.23) were independently associated with poor survival. Moreover, the median survival time of patients with active disease and extremely high sIL-2R level (≥ 3 × median, 2073 U/mL) was 0.9 months, whereas the other groups did not reach the median.

Conclusion
Although HSCT is the only curative treatment for sCAEBV, the strategies need improvements in high-risk cases, especially of high sIL-2R.

Disclosures
Arai: ONO PHARMACEUTICAL CO., LTD.: Honoraria, Research Funding; CHUGAI PHARMACEUTICAL CO., LTD.: Honoraria, Research Funding; Kyowa Kirin CO., LTD.: Honoraria, Research Funding; Abbvie: Honoraria; BMS: Honoraria; Elsai Co Ltd: Research Funding; Abbott Japan LLC: Honoraria; Nippon Shinyaku Co. Ltd: Honoraria, Research Funding; Otsuka Pharmaceuticals Co. Ltd: Research Funding; Novartis Pharma KK: Honoraria; Takeda Pharmaceuticals Co Ltd: Honoraria, Research Funding; Shionogi & Co Ltd: Research Funding; Asahi Kasri Pharma Corporation: Research Funding; Sanofi: Honoraria; Pfizer japan: Honoraria; Astellas Pharma Inc.: Honoraria. Yamamoto: Bristol-Myers Squibb Company: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Eisai Co., Ltd.: Honoraria; Kyowa Kirin Co., Ltd.: Honoraria; NIPPON SINYAKU CO., LTD: Honoraria; Novartis Pharma: Honoraria; ONO PHARMACEUTICAL CO.: Honoraria; Otsuka Pharmaceutical: Honoraria; Pfizer Japan Inc.: Honoraria; Takeda: Honoraria. Nakamae: Astellas Pharma Inc.: Honoraria; Otsuka Pharmaceutical Co., Ltd: Honoraria; ONO PHARMACEUTICAL CO., LTD.: Honoraria; Simon-Kucher & Partners: Honoraria; Sumitomo Dainippon Pharma Co., Ltd.: Honoraria; Takeda Pharmaceutical Company Limited.: Honoraria; Novartis: Honoraria, Research Funding; Pfizer Japan Inc.: Honoraria; Bristol-Myers Squibb　Company: Honoraria, Research Funding; Alexion: Research Funding; PPD-SNBL K.K: Research Funding; CMIC HOLDINGS Co., Ltd: Research Funding. Ichinohe: Repertoire Genesis Inc.: Honoraria, Research Funding; Novartis Pharma K.K.: Honoraria; Celgene: Honoraria; Zenyaku Kogyo Co.: Research Funding; Takara Bio Inc.: Research Funding; Taiho Pharmaceutical Co.: Research Funding; Sumitomo Dainippon Pharma Co.: Honoraria, Research Funding; Otsuka Pharmaceutical Co.: Research Funding; Nippon Shinyaku Co: Research Funding; Ono Pharmaceutical Co.: Honoraria, Research Funding; Kyowa Kirin Co.: Honoraria, Research Funding; FUJIFILM Wako Chemicals.: Honoraria, Research Funding; Daiichi Sankyo: Research Funding; Eisai Co.: Honoraria, Research Funding; CSL Behring: Honoraria, Research Funding; Chugai Pharmaceutical: Research Funding; Bristol-Myers Squibb: Honoraria; Takeda Pharmaceutical Co.: Honoraria; AbbVie Pharma: Research Funding; Astellas Pharma: Honoraria, Research Funding. Atsuta: Astellas Pharma Inc.: Speakers Bureau; Mochida Pharmaceutical Co., Ltd.: Speakers Bureau; AbbVie GK: Speakers Bureau; Kyowa Kirin Co., Ltd: Honoraria; Meiji Seika Pharma Co, Ltd.: Honoraria.