Proteins of S100 group, produced by phagocytes represent endogenous activators of innate immune responses. Role of these
proteins in the etiopathogenesis of
cholelithiasis remains unknown. The studies aimed at the morphometric evaluation of S100A8 and
S100A9 protein expression in gallbladder mucosa in patients with acute and chronic calculous
cholecystitis (n = 71). The presence of
proteins was detected by immunohistochemistry while quantitative analysis employed the spatial visualization technique. We found the immunopositive expression of the two studied
S100 proteins in neutrophils and monocytes/macrophages of the gallbladder's wall and a higher expression in
acute cholecystitis. Quantitative study revealed higher immunoexpression of S100A9 over S100A8 in both studied groups of patients. Moreover, a reciprocal linear relationship between the expression of the studied
proteins and a positive correlation between expression of either S100A8 or S100A9 and inflammatory activity (grading) in the gallbladder wall were found. The expression of
S100A8 protein in the chronic
cholecystitis group and in older patients correlated with
leukocytosis, which suggests the role of S100A8 particularly at the chronic stage of
cholecystitis. The obtained results indicated close relationship between S100A8 and S100A9
proteins in their proinflammatory functions. The increased expression of only one of them can be recognized as a useful index of local inflammatory activity in calculous
cholecystitis.