TGFB1 and rheumatoid arthritis: We also confirmed that low-intensity PE down-expressed genes (Il2, Il10, Il12a, Il23a, and Tgfb1) and signaling pathways (cytokine–cytokine receptor interaction, Th1 and Th2 cell differentiation, Th17 cell differentiation, and chemokine signaling pathway) that are identified in the phases of maturation and amplification of the systemic immune response that predates RA [2].