NK cell function in this model was assessed by Vandenhaute et al. NK cells in CFA-treated IFN-γ-KO mice were reduced in number and showed increased proportion of activation markers and impaired cytotoxicity with reduced expression of perforin and granzyme B compared to WT, similar to that seen in patients with SJIA. The gene discussed is IFNG; the disease is systemic-onset juvenile idiopathic arthritis.