GRK6 and autoimmune disease: GRKs, especially GRK6, are highly expressed in vertebrate immune organs and peripheral blood cells.13, 14 GRK6 knockout (GRK6−/−) mice show increased severity of acute inflammatory arthritis15 and colitis16 because of enhanced granulocyte chemotaxis, and develop autoimmune diseases due to impaired macrophage engulfment.17 GRK6 regulates chemotaxis through SDF/CXCLs-CXCR4,18, 19 leukotriene B4-induced CGRP receptor20 and BLT receptor21 activation.