TNF and polyarticular arthritis: Similar to the TNF-α Tg mice, which begin to develop spontaneous polyarthritis at the age of 7 weeks as previously reported [41], the TNF-GILZ double Tg mice also started to develop polyarthritis (Fig 1C), indicating that mesenchymal lineage cell expression of GILZ does not counteract or delay the development of TNF-α -induced arthritis in mice expressing high levels of human TNF-α globally.