TRBV5-4 and rheumatoid arthritis: Moreover, analysis of TCR Vβ and Jβ gene expression showed increased frequency of expression of certain TRBV and TRBJ genes, including TRBV5-4–TRBJ2-3 and TRBV29-1–TRBJ2-7 in ACPA+ RA compared to HCs (Supplementary Fig. 5c, d).