Blood cytokine and complement levels in patients with sepsis.

We measured serum levels of endotoxin, cytokines, and eicosanoids and investigated their relationship to serum complement levels in patients with sepsis. Serum endotoxin (Et) levels (5.3 +/- 2.4 pg/ml) were within the normal range, but levels of tumor necrosis factor-alpha (TNF-alpha, 114 +/- 104.94 pg/ml), interleukin 6 (IL-6, 86.7 +/- 50.9 pg/ml), interleukin 8 (IL-8, 86.8 +/- 49.7 pg/ml), type-II phospholipase A2 (type II PLA2, 211.3 +/- 193.9 ng/ml), leukotriene B4 (LTB4, 88.7 +/- 27.2 pg/ml), thromboxane B2 (TXB2, 58.7 +/- 50.9 pg/ml) and 6-keto-prostaglandin F1 alpha (PGF1 alpha, 21.0 +/- 11.0 pg/ml) levels were above normal. Levels of C3a (1088.4 +/- 83.8.7 ng/ml) and C4a (1951.5 +/- 1697.8 ng/ml) were also above normal; C3 (66.0 +/- 25.6 mg/dl) and C4 (23.6 +/- 5.3 mg/dl) were within the normal range, and C5a was lower than the detectable limit in all but one of the subjects. Serum TNF-alpha was significantly correlated with C3a (p < 0.001). Serum IL-6 had a significant negative correlation with C3 (p = 0.002) and C4 (p = 0.010). Type II PLA2 was significantly correlated with C3a (p < 0.001). There were no significant correlations between serum Et or IL-8 and serum C3, C4, C3a or C4a. Our findings suggest that increased levels of TNF-alpha, IL-6, and Type II PLA/ in patients with sepsis contribute to activation of the complement system.