Cats with leukocytosis had higher duodenal/proximal jejunal numbers of S100A8/A9+ (median: 8.5 vs. 4; p = 0.012) and S100A12+ cells (median: 6.5 vs. 3; p = 0.014) than cats with normal peripheral leukocyte counts. The gene discussed is S100A12; the disease is Increased total leukocyte count.