ENTPD1 and rheumatoid arthritis: KEGG pathway analysis of the upregulated proteins in ENTPD1+CD55+ cells indicated enrichment for proteins involved in rheumatoid arthritis (e.g., HLA-DRA, ICAM1) and ECM–receptor interaction (e.g., type I collagen, Laminin subunit alpha-5, integrin-subunit alpha-6) (Table 1 and Table 2).