PDE4A and psoriasis: Recent advances in understanding psoriasis pathophysiology have spurred the development of additional therapeutic targets, including IL-36 inhibitors, phosphodiesterase (PDE)-4 inhibitors, Janus kinase (JAK) inhibitors, tyrosine kinase 2 (TYK2) inhibitors, RORγt inhibitors, and A3 adenosine receptor agonists [13,14,15].