Patients
All patients were treated and followed-up at Shanghai Children’s Medical Center. The medical records of patients aged 1-2 years who underwent liver transplantation between January 2012 and January 2019 were reviewed. All patients included in this study were diagnosed with PTLD during the aforementioned period. Patients who died during the follow-up period were excluded from this analysis. The control patients were matched 1:2 according to the type of organ transplanted and the period since transplantation (within 1 year). The control patients were recruited from a cohort of transplant recipients who did not have PTLD and who underwent a transplant during the same period as the study subjects. Clinical characteristics and laboratory findings were extracted from each patient’s medical records and analyzed.