Immunohistochemical study of carbonic anhydrase isozymes in human skin.

An increasing number of carbonic anhydrase (CA) isozymes have been discovered in human organs. However, there is little evidence concerning their expression in mammal skin, humans included, and the isozymes involved have not been identified yet. In this study, the distribution of three CA isozymes I, II and IX in human skin from healthy subjects was investigated using an immunohistochemical technique. Specific staining for CA I and II was detected in the basolateral plasma membrane of the epithelial cells of the spinous and basal layers of epidermis as well as in the endothelium of capillaries in the papillary dermis. A marked CA II immunoreactivity was mostly found in secretory cells of the sweat glands. No signal for CA IX was detected but on the plasma membranes and the cytoplasm of cells surrounding the hair shaft. The significance and biological role of CA isozymes expression in human skin is discussed.