PDE4A and psoriasis: Different studies have suggested the involvement of PDE4 in several pathophysiological processes, supporting the interest of this subfamily of enzymes as potential therapeutic targets for the treatment of a myriad of disorders, including dermatoid arthritis, atopic dermatitis, asthma, chronic obstructive pulmonary disease (COPD), psoriasis, lupus and cardiovascular diseases [2,3,14].