Ruxolitinib (Ruxo) reduces neutrophil activation in primary HLH. (A) Representative plots showing surface expression of TREM-1 on neutrophils. Graph depicts the frequency of splenic TREM-1⁺ neutrophils (right panel). (B) Representative plots showing intracellular TNF-α staining in splenic neutrophils gated on TCRb⁻CD11b⁺Ly6C^intLy6G⁺ cells from naive or LCMV-infected Prf1^−/− mice that were treated or not with αIFN-γ or Ruxo. Graph depicts the frequency of TNF-α⁺ neutrophils (right panel). Data (mean ± standard deviation) are representative of 2 independent experiments (n = 3 mice per group). *P < .05, **P < .01, ***P < .001, ****P < .0001.