Figure 1.

Cytomegalovirus (CMV) viral load at start of the first, second and third CMV reactivations. Median (range) CMV viral load (VL) at the time of the first, second and third CMV reactivations is shown for all patients and high-risk CMV-negative donor/CMV-positive recipient (D-/R+) pairs. It should be emphasized that VL measurements were not standardized among centers. CMV load was measured by quantitative polymerase chain reaction from whole blood (9 centers) or plasma (1 center) using either a commercial assay (Abbott RealTime CMV; 2 centers) or validated in-house protocols and equipment (8 centers). Accordingly, treatment-requiring viral load thresholds were center-specific and no analysis correlating spot-forming-cell counts to VL was planned in this study.