VZV- and HSV-specific T-cell reconstitution at start of study drug and at 1 year after transplantation or VZV disease (whichever occurred first). A positive result was defined as a stimulation index of 3 or greater. Shown is the proportion of patients with a positive response. None of the differences are statistically significant. Phytohemagglutinin (PHA) responses were present in all but one patient in both study arms.