Cathelicidin

Members of the cathelicidin family of antimicrobial polypeptides are characterized by a highly conserved region (cathelin domain) and a highly variable cathelicidin peptide domain. Cathelicidin peptides have been isolated from many different species of mammals. Cathelicidins were originally found in neutrophils but have since been found in many other cells (e.g., in macrophages activated by bacteria, viruses, fungi, or the hormone 1,25-D). The cathelicidin family shares primary sequence homology with the cathepsin family of cysteine proteinase inhibitors, although amino acid residues thought to be important in such protease inhibition are usually lacking.

Richard L. Gallo and colleagues recently noticed that patients with rosacea had elevated levels of cathelicidin and elevated levels of stratum corneum tryptic enzymes (SCTEs). Antibiotics have been used in the past to treat rosacea, but antibiotics may only work because they inhibit some SCTEs.