The frequency of DPTs in peripheral blood does not increase in HIV, HCV, or melanoma; however, this subpopulation exhibited a higher expression of surface activation markers (i.e. HLA-DR and CD38) and greater cytokine production (i.e. interferon-γ and TNF-α) in individuals with these diseases when compared to controls [7,9,10,14]. The gene discussed is CD38; the disease is melanoma.