FIGURE 8.

IL-18 is associated with anemia and exerts a negative effect on erythropoiesis in vivo. MAS was induced in WT and IL-18BP KO mice. Blood and organs were sampled at sacrifice (day 7). (Ai) The correlation between anemia and the amount of free IL-18 in the circulation is shown (WT: n = 22 and KO: n = 20, from four independent experiments). (Aii) Reticulocyte numbers in the blood were determined (WT: n = 10 and KO: n = 9). (Bi) Calculated number of Ter119⁺ cells in BM of one hind leg, based on flow cytometric analysis. (Bii) Absolute numbers and (Biii) proportion of CD45⁻ erythroid precursor populations (C0 to C5 in order of maturation) in BM of one hind leg. (C) Flow cytometric analysis of BM cells allowed an estimation of the percentage of (Ci) CD45⁺, (Cii) CD45⁻, (Ciii) CD11b⁺, and (Civ) F4/80⁺ cells (WT: n = 10 and KO: n = 9, from two independent experiments). (D) Representative histograms of the in vivo expression of IL-18Rα (Di) by erythroid precursor populations and (Dii) by other cell types in BM of naive WT mice (n = 4, from one experiment). (E) TNF-α, IL-6, and GM-CSF levels were assessed in the circulation of CpG-injected WT and IL-18BP KO mice, respectively (n = 10 and n = 9). (F) Transcript levels of Hamp1 (encoding hepcidin 1) normalized to the housekeeping gene Rpl32 in liver. Results are represented as mean ± SD, and each individual symbol represents one mouse, n ≥ 7 from at least two independent experiments. Statistical analyses were performed using Mann-Whitney tests.