Ruxolitinib therapy reduces macrophage activation, tissue infiltration, and tissue damage. (A) Representative fluorescence-activated cell sorter analysis of liver MNCs gated on CD64⁺ Ly6C⁺ inflammatory macrophages in control (B6) and Prf1^−/− mice nontreated (day 7) or treated with ruxolitinib for 14 days (day 28). (B) Frequency and absolute number of inflammatory CD64⁺Ly6C⁺ macrophages in the liver at the indicated point (dpi [days postinfection]; upper and lower, respectively). Data (mean ± SEM) are representative of 3 to 4 independent experiments with at least 3 mice in each group. ***P < .001. (C) Hematoxylin and eosin staining of liver sections from untreated control mice (B6) (days 11 and 28) and Prf1^−/− mice either nontreated (day 11) or treated with ruxolitinib and analyzed at day 28 postinfection (10× objective lens). Periportal and parenchymal infiltrates are depicted with arrows. One representative of at least 5 randomly chosen fields is shown. (D) Aspartate aminotransferase (ASAT), alanine transaminase (ALAT), and lactate dehydrogenase (LDH) levels in the serum from (B6) and Prf1^−/− mice either nontreated or treated with ruxolitinib from day 7 postinfection for 14 days, and measured at different points. *P < .05; **P < .005; ***P < .001; ****P < .0001). Dotted lines represent normal values. (E) Hematoxylin and eosin staining of spleen sections from control (B6) at day 11 and day 28 and Prf1^−/− mice either nontreated (day 11) or treated with ruxolitinib and analyzed at day 28 postinfection (5× objective lens). One representative of at least 5 randomly chosen fields is shown. Data (mean ± SEM) are representative of 3 to 4 independent experiments with at least 3 mice in each group.