Interestingly, in vitro treatments (Additional file 2: Supplementary methods) of joint-infiltrating neutrophils with conventional mCTLA4Ig dampened the secretion of tumor necrosis factor-α (TNF-α) (Fig. 6E), a well-known pathogenic cytokine in human and mouse arthritis [1, 44, 45]. Here, TNF is linked to arthritic joint disease.