A pilot study of L-asparaginase monotherapy for Epstein-Barr virus positive T or NK cell lymphoproliferative disease (Chronic active Epstein-Barr virus infection)

INTERVENTION: One cycle of L‐asparaginase monotherapy CONDITION: Epstein‐Barr virus positive T or NK cell lymphoproliferative disease (Chronic active Epstein‐Barr virus infection) PRIMARY OUTCOME: Decrease rate of EBV‐DNA titer in peripheral blood (whole blood) SECONDARY OUTCOME: Overall response rate; ORR (rate of complete response (CR) or partial response (PR)), the rate of adverse events, and decrease rate of EBV‐DNA titer in peripheral blood (plasma) INCLUSION CRITERIA: (1)Patients of Epstein‐Barr virus positive T or NK cell lymphoproliferative disease, diagnosed according to the following: 1) EBV‐DNA titer in peripheral whole blood >= 1x10E2.5 copy/ugDNA 2) Detection of EBV infected T cell or NK cell in the tissue or peripheral blood 3) Persistent infectious mononucleosis‐ like symptoms with fever, liver dysfunction and lymphadenopathy for 3 at least months 4) Monoclonal proliferation of EBV‐ infected cells 1,2 and 3 or 4 (2)Age 14‐69 years (3)Performance status (ECOG) 0‐2 (4)Patients with sufficient hepatic, renal, cardiac, and pulmonary function (5)A patient whose written informed consent is gettable before registration (when a patient is a minor, patient's and parent's written informed consent should be obtained.)