Intracellular monocyte cytokine production and CD14 expression are up-regulated in severe vs mild chronic heart failure

Background: The role of circulating monocytes in the process of low-grade inflammation, characteristic of chronic heart failure (CHF), has recently been questioned. Lipopolysaccharide (LPS) desensitization has been proposed to mediate reduced monocyte cytokine elaboration in patients with severe CHF. Methods: Intracellular monocyte production of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor (TNF)-alpha, and monocyte CD14 expression were measured flow-cytometrically without and after 8-hour LPS stimulation in 46 patients with CHF and in a healthy control group. Results: Basal cytokine concentrations were similar for the control and the mild CHF groups (New York Heart Association [NYHA] Class I or II). After LPS stimulation, IL-6 (P = 0.002) and TNF-alpha levels (P = 0.001) were lower in the latter group, whereas IL-1 beta production was comparable. For the moderate-severe CHF patients, unstimulated IL-1 beta (p = 0.04) was higher, whereas IL-6 (P = 0.2) and TNF-alpha (p = 0.1) levels were not different from the controls. Measurement of LPS-stimulated cytokine production showed no differences between the control group and patients with moderate-severe CHF (all p > 0.5). Upon comparing mild vs moderate-severe CHF patients, higher levels of unstimulated cytokine production (IL-1 beta, p = 0.002; IL-6, p = 0.01; TNF-alpha, P = 0.003), stimulated IL-1 beta (p = 0.002) and IL-6 (p = 0.008) were found in the latter patients. CD14 expression in the moderate-severe CHF group was higher than in the mild-CHF group (P = 0.03) and was strongly related to stimulated IL-1 beta (r = 0.62, p < 0.0001), IL-6 (r = 0.56, p = 0.0002) and TNF-alpha (r = 0.41, p = 0.006) production. Conclusions: CD14 expression and monocyte cytokine production, both unstimulated and after LPS stimulation, are increased in moderate-severe CHF when compared with mild CHF. These data suggest that circulating monocytes, possibly via increased CD14 expression, may play a significant role in the immunologic dysbalance observed in advanced CHF.