Cytokine production by fibroblasts is not only important for immunological and inflammatory reactions in the epidermis and mucosa, but also for growth and differentiation of epithelial cells. To characterize the role of fibroblasts in the oropharyngeal mucosa, the expression of a panel of cytokines and cytokine receptors by fibroblasts isolated from normal human oropharyngeal mucosa was investigated by enzyme-linked immunosorbent assay (ELISA), reverse transcribed polymerase chain reaction (RT-PCR) and flow cytometry (FACS). Oropharyngeal fibroblasts produced the proinflammatory cytokines interleukin 1 alpha (IL-1 alpha), IL-6 and IL-8 without addition of phorbol-12-myristate-13-acetate (PMA) or biological response modifiers, suggesting an active involvement of these cells in host defence mechanisms. Keratinocyte growth factor (KGF), a growth factor for epithelial cells, and the angiogenetic fibroblast growth factors acidic and basic FGF (aFGF, bFGF) were also synthesized. Expression of receptors for IL-1, IL-4, IL-6, platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) was found. These results indicate that oral fibroblasts are capable of producing a number of cytokines without the need for additional stimuli and emphasize their active regulatory role in the maintenance of the oral mucosa.