Human cytomegalovirus-specific CD4+ and CD8+ T-cell response determination: Comparison of short-term (24 h) assays vs long-term (7-day) infected dendritic cell assay in the immunocompetent and the immunocompromised host

Human cytomegalovirus (HCMV)-specific CD4+ and CD8+ T-cells were measured in the immunocompetent host as well as in 13 solid-organ transplant recipients (SOTR), and 12 young hematopoietic stem cell transplant recipients (HSCTR) by using a long-term (7-day) assay based on PBMC stimulation by HCMV-infected dendritic cells (iDC), and two short-term (24 h) assays, one for CD4+ stimulation by infected cell lysate (iCL), and the other for CD8+ stimulation by a pool of 34 epitopic peptides (pep-pool). In the immunocompetent, the number of T-cells activated by either iCL or the pep-pool was significantly reduced with respect to iDC. In both SOTR and HSCTR, the number of T-cells activated by iDC was comparable to that activated by iCL or the pep-pool. A significant correlation between iDC-activated T-cells and T-cells activated by either iCL or the pep-pool was observed. In conclusion, whenever a rapid result is needed, short-term assays may efficiently replace the iDC assay.