S100A7 and psoriasis: Twenty-one S100 proteins are known, of which S100A7 (psoriasin), S100A8 (calgranulin A), S100A9 (calgranulin B), S100A12 (calgranulin C), and S100A15 have antimicrobial effects and their expression levels are increased in the lesional skin and serum of psoriasis patients [19].