Granulocyte-macrophage colony-stimulating factor in psoriasis.

Granulocyte-macrophage colony-stimulating factor (GM-CSF), a product of activated T lymphocytes, macrophages, endothelial cells, fibroblasts, and keratinocytes, is thought to play an important role in inflammatory reactions by 'priming' or enhancing the functions of neutrophils and macrophages. The aim of this study was to determine whether GM-CSF is detectable in psoriatic lesions. No GM-CSF was detected by ELISA in the suction blister fluids raised on normal, psoriatic uninvolved or involved skin. In contrast, although we could not detect GM-CSF in most of the extracts from noninflammatory stratum corneum, it was readily detected in most of the scale extracts from psoriasis and sterile pustular dermatoses, and its level was significantly higher than that from the controls. These results suggest that in psoriasis GM-CSF may amplify and modulate inflammatory reactions and activated T cells.