Specifically, Tph cells are highly present in patients with rheumatoid arthritis and produce CXCL13, IL-21, ICOS, and MAF, which promote CXCR5+ cell recruitment, local auto-antibody production and inflammatory cytokine production45–47 Enrichment analysis of our data shows the red module is significantly enriched with Tph-associated genes with high KME such as BATF, CCR2, CD4, CXCL13, ICOS, PD-1, SH2D1A, SLAMF6, and TIGIT. Here, ICOS is linked to rheumatoid arthritis.