Production of interleukin (IL)-1β, IL-1 receptor antagonist and IL-10 by blood mononuclear cells in chronic arthritis

Joint erosion is a prevalent feature of rheumatoid arthritis OCA) but not of many other chronic inflammatory arthritides (non-RA). Joint destruction is mediated by cytokines, primarily interleukin (IL)-1 and tumour necrosis factor, Less erosive activity in patients with non-RA compared to RA might be related to factors that inhibit production and/or function of IL-1. Release of IL-1 beta, and the two antagonists, IL-1 receptor antagonist (IL-1ra) and IL-10 from blood mononuclear cells were therefore quantitated by ELISA in 22 patients with RA, 11 with non-RA and 15 healthy age-matched controls. Release of IL-1 beta was comparable between the three groups but only detectable in cultures stimulated with lipopolysaccharide; it decreased in patients treated with prednisolone: 3.8 ng/10(6) monocytes (median) vs 11.7 (P=0.045). Release of IL-1ra was in all but IgG-stimulated cultures comparable between groups. The ratio of HL-1ra/IL-1 beta was elevated in LPS-stimulated cells from RA patients only: 2.0 versus 1.3 (P=0.02). In contrast, IgG-induced IL-1ra release was significantly elevated only in non-RA patients: 95 ng/10(6) monocytes vs 40 (P=0.014), and the levels correlated positively to those of blood CRP (P = 0.02). Though stimulated release of IL-10 was similar between the three groups, the levels were lower in non-erosive than erosive arthritis patients, and controls (P=0.05). In conclusion, increased IgG-stimulated IL-1ra release and elevated IL-1ra/IL-1 beta ratio may protect against actions of IL-1 in vivo, and decreased release of IL-10 might be related to features of non-erosive arthritis. (C) 2000 Academic Press.