CD40 and HIV-1 infection: Since monocyte phenotype perturbations in HIV-1 infection and changes in monocyte phenotype with antiretroviral therapy (ART) are incompletely defined, we implemented a flow cytometry panel for cryopreserved cells that explored the expression and density of: activation and maturation markers, HLA-DR, CD38, CD13, and CD83; the co-stimulatory molecules CD40 and CD86; chemokine receptors CCR2 and CX3CR1; and the scavenger receptors CD36 and CD163.