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 examined 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 controls were examined. Production of IL-6 and IL-8 was assessed by specific ELISA, and the levels of IL-6 and IL-8 mRNA were determined by reverse transcriptase polymerase chain reaction (RT-PCR).


RESULTS
Basal production of both IL-6 and IL-8 was significantly increased in scleroderma fibroblasts compared with controls. When cells were stimulated with either IL-1beta (50 pg/ml) or tumor necrosis factor-alpha (TNF-alpha: 10 ng/ml), the production of IL-6 and IL-8 was predominantly increased in both cell strains and there was no significant difference in the production of IL-6 and IL-8 between them. When normal fibroblasts were stimulated with IL-1beta for 48 h and subcultured, both IL-6 and IL-8 production were significantly increased, and production remained elevated even after 3 passages. RT-PCR revealed that IL-6 and IL-8 mRNA were detected in scleroderma fibroblasts but not in normal skin fibroblasts without cytokine stimulation. When stimulated with IL-1beta, both cell strains expressed IL-6 and IL-8 mRNA to almost the same extent.


CONCLUSIONS
Increased production of IL-6 and IL-8 by scleroderma fibroblasts suggests that these cells may have been stimulated by certain cytokines in vivo.
Kadono
T
T
Department of Dermatology, Faculty of Medicine, University of Tokyo, Japan.
Kikuchi
K
K
Ihn
H
H
Takehara
K
K
Tamaki
K
K
D002478:Cells, Cultured; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000097:blood / Q000378:metabolism*; D016209:Interleukin-8 / Q000097:blood / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012595:Scleroderma, Systemic / Q000378:metabolism*; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D007375:Interleukin-1; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha