Augmented interleukin-6 secretion in collagen-stimulated peripheral blood mononuclear cells from patients with systemic sclerosis.
BACKGROUND
Systemic sclerosis is an autoimmune disease that is associated with excessive fibroblast proliferation and collagen deposition in various tissues. Interleukin-6 (IL-6) is produced by fibroblasts, activated T and B lymphocytes, which maybe involved in the pathogenesis of systemic sclerosis.


OBJECTIVE
This study was performed in order to determine whether IL-6 could be detected specifically in collagen-stimulated peripheral blood mononuclear cells from patients with systemic sclerosis.


METHODS
We clinically evaluated seven patients with systemic sclerosis for disease duration and organ involvement and analyzed in vitro the ability of their peripheral blood mononuclear cells and those of disease-free controls, in the presence of concanavalin A, human type I collagen, and the mast cell mediator, heparin to secrete IL-6 spontaneously by a sensitive ELISA.


RESULTS
Interleukin-6 production by nonspecific stimulation with concanavalin A did not differ between patients with systemic sclerosis and controls; however, collagen stimulation significantly increased IL-6 production in patients with systemic sclerosis; mean 1728 pg/mL versus a mean of 386 pg/mL in controls P = < .05). Collagen-stimulated IL-6 levels > 2000 pg/mL were obtained in 86% of patients with systemic sclerosis compared with none in the controls. In patients with systemic sclerosis with a shorter disease duration, greater spontaneous as well as collagen- and heparin-stimulated IL-6 production was observed, whereas decreased IL-6 levels were noted with longer disease duration (> 21 years).


CONCLUSIONS
The results of this study suggest that peripheral blood mononuclear cells from patients with systemic sclerosis are specifically sensitized to human type I collagen to produce increased levels of IL-6, which may play a role in the pathogenesis in this fibrotic disorder.
Gurram
M
M
North Shore University Hospital, Department of Pediatrics, Cornell University Medical Center.
Pahwa
S
S
Frieri
M
M
D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology*; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D012595:Scleroderma, Systemic / Q000097:blood* / Q000378:metabolism
D015850:Interleukin-6; D003208:Concanavalin A; D003094:Collagen