Production of TNF by monocytes of patients with early rheumatoid arthritis is increased

We studied the production of tumour necrosis factor alpha (TNF) by monocytes of patients with early rheumatoid arthritis (RA) before starting disease modifying anti-rheumatic drug treatment and a median 6 months (range 5-11 months) later, and correlated the pre-treatment results with 3-year prognosis. Monocytes of patients (n = 14) and controls (n = 14), isolated by the density gradient centrifugations, were cultured for 24 h with Escherichia coli lipopolysaccharide (LPS) 0-10 micrograms/ml. Before treatment, levels of TNF were higher in LPS-stimulated RA monocyte cultures than in the control cultures; differences were statistically significant in LPS 10 and 0.01 micrograms/ml. At 6 months, respective differences were not significant. Levels of TNF before treatment did not correlate to clinical or laboratory parameters of inflammation, or development of erosions. The results indicate that monocytes of patients with early RA are primed, and that the state of priming decreases during treatment.