Membrane CD40L expression by stimulated CD3+CD8- circulating T lymphocytes in UNPC patients and healthy donors. The analysis was carried out using a two-color flow cytometric assay coupled with a previously described gating strategy . The percentage of stimulated CD3+CD8- expressing membrane CD40L is indicated on the y axis. A significantly lower percentage of CD3+CD8- T cells from UNPC patients up-regulated CD40L upon stimulation as compared to controls (p < 0.001). The difference remained statistically significant also after correction for the number of CD4+ cells.