This is an investigator-initiated, open-label, single-arm, dose-escalation exploratory study to evaluate the safety, tolerability, and preliminary efficacy of EBV-AST cell injection in adults with EBV-associated lymphoproliferative disorders, including post-transplant lymphoproliferative disease (PTLD) and EBV-positive lymphomas. Participants will receive EBV-AST cell infusions intravenously every 2 weeks for up to 3 infusions at escalating dose levels. The primary objective is to assess safety and determine a potential optimal biologically active dose. Secondary objectives include preliminary tumor response and EBV-related virologic outcomes, as well as cellular PK/PD.