CD4 and autoimmune disease: Loss of CD6 impairs migration of T cells,9 and a CD6 mAb inhibits migration of CD4+ T cells across the blood–brain barrier.30 In an experimental autoimmune encehalomyelitis model of autoimmune disease, CD4+ cells showed reduced infiltration of the spinal cord in transgenic mice expressing CD5 with a deletion, SSDS, overlapping the SDSDY sequence, compared with the wild‐type transgene.12 A study exploiting CD6 as a homing receptor shows its signalling effects on cytoskeletal activity and includes microscopy demonstrating a link with the actin cytoskeleton.31