Abstract
Depositions of immune-complexes are responsible for many of the pathological features of systemic lupus erythematosus (SLE). For example, immune-complex-induced tissue damage in glomerulonephritis has been shown to be mediated, at least in part, by interleukin (IL)-1. Inappropriate production or function of IL-1 may therefore contribute to disease manifestations in SLE. We investigated lipopolysaccharide (LPS)- and adherent IgG-stimulated release of IL-1β, IL-1 receptor antagonist (IL-1ra) and IL-10, a potent modulator of IL-1, by blood mononuclear cells from patients with SLE. Mediator production was measured as ng cytokines/106 monocytes and compared with clinical parameters. Release of IL-1β was only detectable in LPS-stimulated cultures and substantially reduced in patients with both active and inactive disease (P < 0.001). LPS-stimulated IL-1ra release was normal and the IL-1ra/IL-1β ratio was therefore increased (P < 0.05) and correlated inversely to prednisolone dosage (P = 0.009). IgG-stimulated release of IL-1ra was reduced in patients with active disease compared to those with inactive disease and controls (P = 0.002). IL-10 release was similar in patients and controls. We conclude that monocytes from patients with active SLE are deficient in Fcγ-R-mediated production of IL-1ra, whereas LPS-stimulated IL-1β release by SLE monocytes is reduced regardless of disease activity. The former may contribute to immune-complex-mediated tissue damage in SLE.