INTERLEUKIN-1 EXPRESSION BY NEUTROPHILS IN RHEUMATOID-ARTHRITIS

Objective-To determine if neutrophils fr om blood and synovial fluid o f patients with rheumatoid arthritis and other joint arthropathies exp ress interleukin-1 beta mRNA. Methods-RNA was isolated from neutrophil s hom patient and control blood, and synovial fluid of patients, probe d in northern blots, and quantified by densitometry. It was also isola ted and analysed from control blood neutrophils after incubation in vi tro with granulocyte macrophage colony stimulating factor (GM-CSF). Re sults--Neutrophils from the synovial fluid of patients with rheumatoid arthritis contained low levels of mRNA for interleukin-1 beta-between 0.1 and 2% of those observed during stimulation of control neutrophil s with GM-CSF for one hour. Higher levels (4-40% of the maximal GM-CSF values) were observed in blood neutrophils from patients with rheumat oid arthritis. Conclusions-Neutrophils contribute to the cytokine netw ork in rheumatoid arthritis. In some circumstances, activation of tran scription may occur within the circulation of these patients.