Transplantaion is recongnized as a cure for CAEBV and EBV associated HLH，however, many patients undergo the reactivation of EBV after transpaltion, patiens may at high risk for recurrence of the disease. PD-1 is a promising therapy to solve this problem.~The present study was a one-arm clinical study, the main subject is to evaluate the effect of PD-1 antibody on the clearance of EBV
PD-1 antibody for reactivation of EBV after transplantation in patients with CAEBV/EBV-HLH