KLRK1 and rheumatoid arthritis: For instance, Groh et al. reported a substantial number of peripheral and synovial CD4+CD28- T cells with expression of NKG2D in patients with rheumatoid arthritis; these CD4+NKG2D+ T cells apparently influenced by pro-inflammatory cytokines such as IL-15 or TNF-α promoted a cytotoxic response against synoviocytes with anomalous expression of MIC molecules[40].