Relationship between interleukin-6 plasma concentration in patients with sepsis, monocyte phenotype, monocyte phagocytic properties, and cytokine production

Monocyte phenotype, their phagocytic capacity as well as the cytokine produ ction from 10 patients with sepsis with low interleukin-6 (IL-6) serum conc entrations (<1000 pg/mL) and 8 patients with sepsis with high IL-6 (<greate r than or equal to>1000 pg/mL) plasma concentrations were investigated with in 24 hours of fulfilling the criteria for sepsis. Monocytes from patients with high IL-6 levels had higher levels of human leukocyte antigen (HLA)-DR , HLA-ABC, CD64, and CD71, and the production of tumor necrosis factor-alph a (TNF-alpha) and IL-8, as well as the capacity of monocytes to phagocytose , was significantly elevated. Of 8 patients with high levels of plasma IL-6 , 4 patients died. In contrast, all 10 patients with low plasma IL-6 concen trations survived until day 28. Patients who died had constant high IL-6 co ncentrations during the first 3 days, whereas IL-6 levels in patients who s urvived decreased by 88%. Our data indicate that IL-6 levels are a better p rognostic parameter in the early phase of sepsis than the monocyte HLA-DR e xpression.