Spontaneous and inducible interleukin 1 production from peripheral blood monocytes in bacterial and viral infections in children.

Peripheral blood monocytes from children with severe bacterial infection showed a high level of spontaneous (unstimulated) production of interleukin 1 (IL-1). In viral respiratory or gastrointestinal infections there usually was little or no spontaneous IL-1 production from monocytes, and the values did not differ from those of children with no infections or inflammatory disease. Lipopolysaccharide-induced IL-1 production from monocytes was slightly but not significantly greater in bacterial infections than in viral infections and controls. Tuberculin (purified protein derivative)-induced IL-1 production from monocytes of patients with viral infections was significantly less than in bacterial infections and also slightly less than in controls. These results indicate that systemic bacterial infections activate spontaneous release of IL-1 from monocytes whereas uncomplicated viral infections usually do not. Tuberculin-inducible IL-1 activity of monocytes appears decreased in viral infections; this might be associated with suppressed cell-mediated immunity in such infections.