PRMT5 inhibition reduces intracellular IFN-γ production in splenocytes derived from mice with HLH. Contours of intracellular IFN-γ in T (A) and NK (B) cells in healthy control mice, mice with HLH and no TX, mice with HLH treated with Rux, and mice with HLH treated with PRT382 started on day 0. Percentage of IFN-γ plus T cells (C) and NK (D) cells in each cohort. Error bars reveal standard deviation. A 1-way ANOVA with Tukey multiple comparisons was used to determine significance. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001.