CCR4 and asthma: The effectiveness of anti-CCL17 and anti-CCL22 antibodies in murine asthma models supports and strengthens a prevalent function for CCR4 on Th2 cells; as Th1 and Th2 responses have opposing functions, CCR4 antagonists act as adjuvants to steer the immune response toward a Th1-type response [39,40,41].