Lipocalin-2 deficiency impairs clinical status and resistance to dissemination of K pneumoniae, and resistance is not correlated to plasma levels of lipocalin-2. (A) Clinical scores for WT/WT, WT/KO, KO/WT, and KO/KO mice. Clinical score criteria: 0: the mouse is unaffected; 1: the mouse is slightly affected, for instance, slight piloerection or commencing waistline; 2: the mouse is affected (marked waistline, piloerection, or slightly decreased mobility); 3: the mouse is clearly affected (ruffled fur, eyes half closed, marked waistline, hunched posture, affected breathing, or decreased mobility); 4: the mouse is very affected and should be killed (ruffled fur, immobile, cold, eyes closed, or condition will proceed to death within hours); and 5: the mouse is dead. Each of the 6 score levels (0-5) is marked with a color. Clinical score distributions for each of the 4 subgroups are shown in percentages. The percentage of mice scoring a particular score is shown in the color allocated to that score. P = .0009 by χ². (B) Bacterial counts are expressed as logarithmic transformed (log₁₀) CFUs per milliliter in BALF for each of the 4 subgroups. No statistical significance between groups as tested by analysis of variance with Tukey's multiple comparison test. (C) Bacterial counts in spleen homogenates are expressed as logarithmic transformed (log₁₀) CFU per milliliter. WT/WT: n = 21, WT/KO: n = 33, KO/WT: n = 25, and KO/KO: n = 38. (D) Lipocalin-2 concentrations in BALF from 5 randomly selected mice from each of the 4 transplanted subgroups 24 hours after inoculation analyzed by enzyme-linked immunosorbent assay. (E) Lipocalin-2 concentrations in plasma from the same mice analyzed in (D). Horizontal lines indicate means. *P < .05, **P < .01, and ***P < .001 by analysis of variance with Tukey's multiple comparison test.