CIRCULATING INTERLEUKIN-6 TYPE CYTOKINES IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

We investigated the serum concentration of interleukin-6 (IL-6) and th e IL-6 family of cytokines (leukemia inhibitory factor (LIF), oncostat in M (OSM) and ciliary neurotrophic factor (CNTF) using an enzyme-link ed immunosorbent assay (ELISA) in 64 patients with systemic lupus eryt hematosus (SLE) and 15 healthy controls, We also examined a possible a ssociation between the serum levels of these proteins and SLE activity as well as correlations between the IL-6 concentration and the levels of LIF, OSM and CNTF, IL-6 was detectable in all 64 patients with SLE and normal individuals, and the level of this cytokine was significan tly higher in patients than in the control group (p < 0.002). LIF, OSM and CNTF were detectable in 9 (14.1%), 6 (9.4%) and 51 (78%) patients , respectively, and undetectable in the majority of healthy individual s, We found positive correlation between the serum concentrations of I L-6, LIF, OSM and CNTF and SLE activity. IL-6 and OSM serum levels wer e also correlated but not IL-6 and LIF or CNTF. In conclusion, an incr ease in the serum levels of IL-6 and, to a lesser extent of LIF, OSM a nd CNTF concentrations may be useful markers for SLE activity.