Anti-CMV T-cell immunity is preserved in vivo after MSC infusion. PBMCs from patient 1 (A) and patient 2 (B) were analyzed with pentamers for CMV-specific CD8⁺ T cells recognizing epitopes of pp65 before and after MSC infusion. (C) Frequency of IFN-γ producing PBMCs from 2 patients in response to pp65 peptides before and 2 weeks, 1 month, and 3 months after MSC infusion were analyzed with Elispot. IFN-γ response to pp65 in PBMCs from 3 healthy CMV-positive donors and 3 healthy CMV-negative donors were used as controls.