Proinflammatory cytokine (IL-1beta, IL-6, IL-12, IL-18 and TNF-alpha) levels in sera of patients with subacute cutaneous lupus erythematosus (SCLE).

Subacute cutaneous lupus erythematosus (SCLE) is a subset of lupus erythematosus that identifies patients with clinically recognized erythematous, nonscarring lesions, photosensitivity and serologic abnormalities. Anti-Ro (SS-A) antibodies are considered to be a typical immunopathologic marker of SCLE. Autoimmune diseases have been also characterized by the disturbances in the cytokine network. The aim of this study was to compare the concentrations of proinflammatory cytokines (IL-1beta, IL-6, IL-12, IL-18 and TNF-alpha) in serum of ANA-positive (antibody against nuclear antigen) and ANA-negative patients with SCLE. Sera samples were collected from 15 patients with SCLE (9 ANA-positive and 6 ANA-negative ones). The preliminary identification of autoantibodies as well as their titers was determined on HEp-2 cells using IIF method. Western blotting (EUROIMMUN) was applied to verify the results of IIF. Proinflammatory cytokine concentrations in the patients' sera samples were determined by enzyme-linked immunosorbent assay (ELISA) (Bender MedSystems). The levels of IL-12 were higher in ANA-positive patients than in ANA-negative subgroups [median (interquartile range), 330 pg/ml (128-708 pg/ml) versus 39.4 pg/ml (31.25-80 pg/ml)]. Similar differences were observed in the level of IL-18 [median (interquartile range), 508.4 pg/ml (180-1222 pg/ml) versus 100.5 pg/ml (78.1-154 pg/ml)]. The differences in TNF-alpha levels between the groups of ANA-positive and ANA-negative patients were at the verge of statistical significance, p<0.05. The sera levels of IL-1beta and IL-6 were low and of no significant difference concerning the ANA-positive and ANA-negative subgroups. Since serum levels of IL-12 and IL-18 were higher in ANA-positive patients than in ANA-negative patients, these cytokines might play an important role in the inflammatory process in SCLE.