Splenomegaly is associated with an expansion of relative frequencies of myeloid cells and a relative contraction of lymphoid subsets. (A) Splenomegaly is dose and TLR7 dependent. Splenomegaly was less pronounced in IFNAR^−/− or IRF7^−/− mice and absent in TLR7^−/− mice upon 1 mg/kg per day of R848 treatment. Spleen weight was first normalized to total body weight of each individual mouse and, second, normalized to the spleen weight of mock-treated animals. Error bars indicate 95% confidence intervals. (B) The prevalence of CD11b⁺ macrophages, CD11c⁺ dendritic cells, and CD11b⁺/Gr-1⁺ neutrophils was increased, whereas that of lymphoid subpopulations was decreased as compared with mock-treated animals (C). Mice were treated with PBS or 1 mg/kg per day R848 for 7 days. Splenocytes were stained with indicated antibodies and relative numbers were assessed by flow cytometry. Error bars indicate standard error. N ≥ 3.