Enhanced expression of the receptor for Granulocyte Macrophage Colony Stimulating Factor on dermal fibroblasts from scleroderma patients

Objective. To elucidate events that initiate the involvement and stimulation of fibroblasts in systemic sclerosis (SSc). Methods. We examined 15 patients with SSc diffuse form, 15 with CREST syndrome, and 5 healthy subjects. Cultured fibroblasts obtained from skin biopsies in SSc involved and non-involved areas and normal skin fibroblasts were cultured with different doses of granulocyte macrophage colony stimulating factor (GM-CSF) to study the effects of this factor on the expression of GM-CSF receptor (GM-CSFR) on fibroblast proliferation and cellular adhesion structures, Results. Cultured fibroblasts obtained from biopsies of normal and SSc skin areas express GM-CSFR and such expression is increased in SSc fibroblasts. GM-CSF stimulation in vitro did not increase SSc fibroblast growth, in spite of a strongly increased expression of the GM-CSFR. The adhesion structures are always more abundant in SSc fibroblasts as compared to healthy cells and GM-CSF seems able to increase cell adhesion plaques. Conclusion. We suggest that shift of fibroblasts toward a more adhesive differentiated pattern, due to or accompanied by an increased expression of GM-CSFR, may be an important event in the pathogenesis of SSc.