CD4 and rheumatoid arthritis: The cit-peptides reactive CD4+ T cells reactive to cit-peptides derived from vimentin, α-enolase, fibrinogen, and TNC were detected in patients with RA with the HLA-DRB1∗04:01 (HLA-DRA1∗01:01/HLA-DRB1∗04:01) as well as in HLA-DRB1∗04:01 transgenic mice immunized with cit-peptides (23, 25, 26, 27, 28, 29).