The high expression of the histamine H4 receptor in cells of hemopoietic lineage and immune cells suggests that this new histamine receptor plays a role in inflammatory and immune responses. Activation of the Histamine receptor can mediate calcium mobilisation and chemotaxis in mast cells.
Preliminary studies on the H4R and specific antagonist (JNJ 7777120 - Johnson & Johnson, VUF6002-Janssen Pharma.) suggests that another rich vein of histamine receptor therapeutics, likely to generate more blockbusters and medical break throughs, could be on the horizon.
Nature Reviews Drug Discover,7, 41-53, 2008, Trends Pharmacol. Sci. 26, 462-469, 2005