S100A8 and epidermal disease: S100A8 and S100A9 are key inflammatory and anti-bacterial proteins in epidermis44, 45, 46, 47 that are highly elevated in some epidermal diseases.45, 48, 49 Recent studies indicate that S100A9 genetic deletion reduces phenotype severity in mouse inflammatory disease models;48 however, we did not observe an appreciable change in disease onset or severity in a S100A9-null/S100A8-null environment.