At present, PDE4 represents an effective therapeutic strategy in many inflammatory conditions, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, psoriasis, atopic dermatitis (AD), inflammatory bowel disease (IBD), rheumatic arthritis (RA), lupus and inflammation of the nervous system [28,29]. Here, PDE4A is linked to inflammatory bowel disease.