PRMT5 expression is present and increases in myeloid and lymphoid mononuclear cell subsets after HLH induction. (A) Percentage of major immune cell types of all singlets from splenocytes of healthy C57bl/6 mice or those with induced HLH. (B) Mean fluorescent intensity (MFI) of CD44 staining in monocytes (Ly6C⁺Ly6G^–) of healthy C57bl/6 mice or those with induced HLH. (C) t-SNE grouping of CD4, CD8, and NK1.1⁺ splenocytes from a healthy or HLH-induced C57bl/6 mouse. Heat maps reveal expression of key marks that allow for subset identification and PRMT5 expression. (D) MFI of PRMT5 in CD4 T cells, CD8 T cells, and NK cells of healthy C57bl/6 mice or those with induced HLH. Error bars show standard deviation. Multiple unpaired t tests with the Holm-Šídák method were used in panels A and D, whereas a Student t test was used in panel B to determine statistical significance. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001. DCs, dendritic cells; ns, no significance; TX, treatment.