EBV load in a PTLD patient following CTL infusions. DNA was extracted from PBMCs and amplified using real-time PCR. The EBV copy number was calculated using a standard curve obtained from dilutions of EBV-positive Raji cell lines. (A) EBV DNA levels in PBMCs of all patients. The black bars show the median value at each time point. The level was taken as 0 where EBV DNA was undetectable. (B) EBV DNA levels in PBMCs of patient 18. (C) EBV DNA levels in PBMCs of patient 2. Pre-inf indicates before CTL infusion; wks, weeks; and mo, months.