Effect of linezolid on cytokine production capacity and plasma endotoxin levels in response to lipopolysaccharide stimulation of whole blood

The purpose of this study was to assess lipopolysaccharide (LPS)-stimulated cytokine production in the presence of linezolid (LZD) in comparison with the drug effect on the plasma endotoxin level. Peripheral venous whole-blood samples collected from five healthy subjects were stimulated with 10 mu g/ml of LPS. LZD was then added to the LPS-stimulated blood samples at concentrations of 0, 2, 4, and 15 mu g/ml, followed by incubation for 24 h at 37A degrees C in a 5% CO2-95% air atmosphere. Supernatants of the resultant cultures were assayed to determine the levels of tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-10, monocyte chemoattractant protein (MCP)-1, and endotoxin. Significant decreases in the levels of TNF-alpha and IFN-gamma were observed in the LZD 2, 4, and 15 mu g/ml groups as compared with that in the 0 mu g/ml group (Dunnett's procedure; P < 0.05). The level of IL-10 tended to increase irrespective of the LZD concentration; however, no significant intergroup differences were observed [analysis of variance (ANOVA); P = 0.68]. No significant decrease of the endotoxin level was observed in the LZD 2, 4, or 15 mu g/ml groups as compared with that in the 0 mu g/ml group, with no significant intergroup differences (ANOVA; P = 0.83). No change in the MCP-1 levels was observed irrespective of the LZD concentration (ANOVA; P = 0.82). To conclude: (1) it appears possible that LZD inhibits the production of INF-gamma and TNF-alpha to a limited extent; (2) LZD did not exert any inhibitory effect on endotoxin production by bacteria, while suppressing cytokine production. The results indicate that LZD may have a significant role in saving the lives of patients with sepsis.