The participation of tumor necrosis factor-α (TNF-α) in a IgE-mediated cutaneous reaction in WBB6F1-W/W^v (W/W^v), mast cell deficient, mice and the effect of prednisolone on this cutaneous reaction were investigated. Mice were passively sensitized by an intravenous injection of monoclonal anti-dinitrophenol (DNP) IgE, and their ears challenged epicutaneously with dinitrofluorobenzene 24 h later. The cutaneous reaction estimated by ear thickness reached a peak 48–72h after the antigen challenge. A monoclonal anti-tumor necrosis factor (TNF)-α antibody inhibited the IgE-mediated cutaneous reaction. An increase of TNF-α mRNA was demonstrated 4h after the application of antigen by the reverse transcriptase-polymerase chain reaction. The injection of recombinant murine TNF-α induced a cutaneous reaction which peaked at 24 h in nonsensitized mice. Prednisolone at doses of 3 to 10 mg/kg clearly inhibited the IgE-mediated cutaneous reaction, however, it did not affect the expression of TNF-α-mRNA. Prednisolone at doses of 1 to 10 mg/kg clearly inhibited the TNF-α-induced cutaneous reaction.

These results suggest that TNF-α plays a role in the IgE-mediated cutaneous reaction in W/W^v mice and that prednisolone inhibits the cutaneous reaction at least in part by inhibiting the action of TNF-α.