Serial analysis of EBV loads in patients with high-level EBV reactivation. (A-M) Routine Q-PCR monitoring of whole-blood samples, collected every 1 to 2 weeks for at least 6 months following allo-HSCT, was used to identify 13 patients with high-level EBV reactivation, defined as an EBV load >20 000 copies per mL blood. The dotted horizontal lines represent the limit of detection of the assay (500 EBV copies per mL); values below this were assigned a value of 250 copies per mL. The dashed vertical arrows indicate the time points at which samples were collected; the solid arrows indicate the time points of rituximab infusion. (E) Patient 5 died of PTLD, (F) patient 6 died of relapsed AML, and (I) patient 9 died of pneumonia (indicated by †).