Time course of circulating acute phase proteins and cytokines in septic patients

This study measured, using ELISA or bioassay methodology, fluctuation in concentration of the circulating cytokines tumor necrosis factor (TNF) and interleukin 6 (IL-6), and the acute phase proteins serum amyloid A (apoSAA) and C-reactive protein (CRP), in five septic patients, during a one-week period starting from the day of diagnosis. All had consistently detectable levels of circulating TNF (range of peak values, 0.6-13.6 ng/ml); two also had high IL-6 levels, while the remaining three had detectable levels only at some time points (range of peak values, 105-315 pg/ml). TNF concentrations fluctuated during the observation period, in some cases with a biphasic temporal pattern. TNF and IL-6 levels were undetectable (below 30 and 100 pg/ml respectively) in the control population with our assays(1,2). ApoSAA concentrations in these patients (range of peak values, 65-975 mu g/ml) were correlated with TNF and with high CRP concentrations (range of peak values, 7-329 mu g/ml). ApoSAA concentrations ranged from 1 to 10 mu g/ml and CRP concentrations ranged from 0.6 to 1.9 mu g/ml in control populations with our assay. Statistically significant correlations between TNF levels and both apoSAA and CRP concentrations were observed for the five patients.