NOD2 and rheumatoid arthritis: Our group identified lncRNA ITSN1-2, a novel RA-associated lncRNA, which is highly expressed in RA peripheral blood and correlates with inflammatory biomarkers (CRP, ESR, TNF-α, IL-17) and clinical scores (DAS28-CRP) [6, 7], Mechanistically, ITSN1-2 upregulation in RA synovium promotes NOD2/RIP2 pathway activation, inducing FLS proliferation and inhibiting apoptosis, thereby exacerbating synovitis [7].