Decreased serum interleukin 1 activity and monocyte interleukin 1 production in patients with fatal sepsis.

The role of interleukin 1 (IL 1) in 16 patients with sepsis and 16 normal controls was investigated. Thymocyte costimulation was used to assay in vitro IL 1 levels produced by adherent cells in the peripheral blood, and in vivo IL 1 levels in the serum. Adherent cells (i.e., monocytes) from nonsurviving septic patients produced significantly less IL 1 activity than cells from healthy controls or surviving patients, either spontaneously or by silica stimulation. In contrast, in vitro IL 2 production by T lymphocytes was not altered in septic patients. Serum IL 1 activity was determined using serum fractions from high-pressure liquid chromatographic gel filtration. Suppressor factors in healthy subjects as well as septic patients usually eluted at molecular weights above 50 kilodaltons, while IL 1-like activity was normally present between 35 and 1 kilodaltons. Sera of nonsurviving septic patients contained significantly less IL 1 compared to that of controls or surviving patients. Thus, decreased serum IL 1 levels and diminished monocyte production of IL 1 appear to be negative prognostic indicators, possibly reflecting a breakdown of mononuclear phagocytes.