Both preclinical and clinical evidence coming from rodent models of RA and RA patients indicate that the CD4+T cell belonging to the Th1 and Th17 subsets, along with M1 macrophages, play a key role in the development and maintenance of RA, as opposed to anti-inflammatory Th2 and Th3 cells, and M2 macrophages that seem to play a protective role on the course of the disease [11]. This evidence concerns the gene CD4 and rheumatoid arthritis.