CD28 and rheumatoid arthritis: Then, we used Venn diagrams to obtain the common hub genes, revealing 11 significant genes shared between RA and AS, namely LYN, HCK, FGR, CXCL8, ARRB2, ITGB2, CD28, FCER1G, VAV1, FCGR2A and ITGA4 (Fig. 5A).