INCREASED PRODUCTION OF INTERLEUKIN-6 AND INTERLEUKIN-8 IN SCLERODERMA FIBROBLASTS

Objective. To determine additional abnormal characteristics related to cytokines in fibroblasts derived from systemic sclerosis (SSc), we ex amined the production of interleukin 6 (IL-6) and IL-8 and their mRNA levels both in scleroderma fibroblasts and in those from normal skin. Methods, Cultured fibroblasts from patients with SSc and healthy contr ols were examined. Production of IL-6 and IL-8 was assessed by specifi c ELISA, and the levels of IL-6 and IL-8 mRNA were determined by rever se transcriptase polymerase chain reaction (RT-PCR), Results. Basal pr oduction of both IL-6 and IL-S was significantly increased in sclerode rma fibroblasts compared with controls. When cells were stimulated wit h either IL-1 beta (50 pg/ml) or tumor necrosis factor-alpha (TNF-alph a: 10 ng/ml), the production of IL-6 and IL-8 was predominantly increa sed in both cell strains and there was no significant difference in th e production of IL-6 and IL-8 between them, When normal fibroblasts we re stimulated with IL-IB for 48 h and subcultured, both IL-6 and IL-8 production were significantly increased, and production remained eleva ted even after 3 passages. RT-PCR revealed that IL-6 and IL-8 mRNA wer e detected in scleroderma fibroblasts but not in normal skin fibroblas ts without cytokine stimulation, When stimulated with IL-1 beta, both cell strains expressed IL-6 and IL-8 mRNA to almost the same extent, C onclusion. Increased production of IL-6 and IL-8 by scleroderma fibrob lasts suggests that these cells may have been stimulated by certain cy tokines in vivo.