The invention provides a flow cytometric method for measuring dendritic cell function in whole blood, comprising: (a) contacting a whole blood sample with a dendritic cell activator; (b) adding to the sample a plurality of dendritic cell-distinguishing antibodies and at least one cytokine-specific antibody; and then (c) flow cytometrically assaying the sample for the binding of the cytokine-specific antibody by at least one distinguishable DC subset. Other assays are presented in which DC activation markers are assessed.