Likewise, we have observed that the activation of transcripts encoding arthritis-associated cytokines (Tnfa, Ifng, il1b) is totally blocked in the joints of mBSA-treated Vav1–/– mice (Figure 2B, top panels) although a significant infiltration of Vav1–/– CD4+ T cells is still observed under such conditions in the joint tissue (Figure 2A). Here, IL1B is linked to arthritic joint disease.