The IL-22R1 transgenic founders show spontaneous multiorgan inflammation. Various organs of IL-22R1 tg mice were stained (hematoxylin and eosin) and examined under the microscope. Inflammation was observed in lung (×20; A), liver (×20; B), colon (×20; C), and kidney (×20; D). Hyperplasia with granulocytic infiltrates was observed in bone marrow (×20; E) and extramedullary hematopoiesis was seen in spleen (×20; F). Arrows show leukocytic infiltrates, and insets show enlargement of the portion of the slide. (G) Total cellularity of the thymus, lymph nodes, bone marrow, spleen, and liver from IL-22R1 tg mice (n = 3) and littermate controls (n = 3). (H) Expression of proinflammatory cytokines is elevated in IL-22R1 tg mice. Cytometric bead array to assay the concentrations of an inflammatory panel of cytokines in the serum of IL-22R1 (n = 7) tg founders and nontransgenic littermates (n = 9). IL-22 production in the serum of IL-22R1 tg and wt mice measured by ELISA (n = 6). The data are represented as the mean ± SEM. *P < .05, **P < .01, ***P < .001; ns, not significant. Images were acquired with an Olympus BX40 light microscope using Image Proplus 6 software.