HCMV-infected CD11c⁺ DCs retain full T cell-stimulatory capacity, and frequencies of PDCs and CD11c⁺ DCs are lower in recipients of renal transplants than in healthy controls. CD11c⁺ DCs were incubated with mock or TB40/E (MOI, 20) in the absence or presence of IFN-blocking cocktail. Equal numbers of viable DCs were cocultured at different ratios with 10⁵ allogeneic CD4⁺ (A) or CD8⁺ (B) T cells from an HCMV-negative control. T cells were stained with the cell-tracking dye CFSE, and proliferation was measured by flow cytometry on day 5 as the percentage of CFSE^low cells among CD3⁺CD11c^- cells. Results of 1 of 3 representative experiments are shown (separate donors). Differences among the various types of allocultures were nonsignificant. Numbers of PDCs and CD11c⁺ DCs in the percentage of PBMCs were determined by flow cytometry in peripheral blood from recipients of renal transplants with or without HCMV infection and from healthy controls (C). Data are shown as mean ± SEM (n = 10 and n = 12 healthy controls; n = 21 and n = 26 patients with active infection; n = 10 and n = 10 patients with no infection) for PDCs and CD11c⁺ DCs, respectively). Relative numbers of both DCs were significantly lower in patients than in healthy controls (P < .005 for PDCs; P < .05 for CD11c⁺ DCs).