Differential cytokine production by the 3 monocyte subsets after activation with LPS. Purified monocyte subsets were treated with increasing doses of LPS. After 18 hours of culture, supernatants were harvested and cytokines and chemokines produced by the classical (•), intermediate (■), and nonclassical (▴) were measured using Bio-Plex human cytokine assay kits. Data are shown as mean ± SD. Representative data are from 4 experiments. *P < .05 (ANOVA). **P < .005 (ANOVA).