Changes in EBV-DNA quantitative levels in the WB of enrolled patients. During the administration of ruxolitinib, we could not measure the levels of EBV mRNA of patients I-1, II-1, and II-2 in our laboratory at Tokyo Medical and Dental University because of the coronavirus disease pandemic in 2019. EBV-DNA quantitative levels (copies per mL) were measured at an alternative laboratory (SRL, Inc). The responses to ruxolitinib at each examination point are represented as follows: CR; PR; PD; SD; and NE, not evaluable.