No difference is found in the amount of inflammatory tissue between c-fos^–/–hTNFtg and hTNFtg mice, but c-fos^–/–hTNFtg mice show a complete lack of bone erosions. Mean areas of (a) inflammation and (b) erosions are shown for wild-type, c-fos^–/–, hTNFtg, and c-fos^–/–hTNFtg mice. Mice lacking the hTNF transgene (wild-type and c-fos^–/–) showed no signs of inflammation. No erosions were detectable in c-fos^–/–hTNFtg mice in contrast to hTNFtg mice. Mice lacking the hTNF transgene also showed no erosions.