Phenotypical characterization of CD56bright NK cells from the synovial fluid of RA patients has shown that synovial fluid CD56bright NK cells share many features with CD56bright NK cells from the blood: they are NKG2A+CD25+KIR− and produce IFN-γ in response to low concentrations of cytokines [68]. The gene discussed is KLRC1; the disease is rheumatoid arthritis.