Monitoring of EBV load in SOT recipients after adoptive transfer of EBV-CTLs. The antiviral responses of patients treated with EBV-CTLs during the first year after infusion are shown. The antiviral activity of the CTLs infused was monitored measuring the EBV-DNA viral load in PBMCs by real-time PCR. Panel A shows the EBV-DNA viral load in patients who received one single dose of EBV-CTLs 2 × 10⁷/m²; panel B shows the load in those who received 5 × 10⁷/m²; and panel C shows the load in those treated with 1 × 10⁸/m² CTLs. Panel D shows EBV-DNA in patients who received multiples doses of 5 × 10⁷/m² EBV-CTLs. Pt indicates patient. Arrows indicate CTL infusions; dotted lines indicate the cutoff of EBV-DNA load above which patients were eligible for CTL infusion.