A reduction in T cell migration to the joint in rheumatoid arthritis (RA) has been observed after treatment with anti-tumour necrosis factor therapy or cyclophosphamide [20-22], and the number of peripheral blood T cells expressing CXCR3 has been shown to rise after anti-tumour necrosis factor therapy for RA, an observation that may be explained by reduced recruitment to the joint [23]. This evidence concerns the gene CXCR3 and rheumatoid arthritis.