CXCL8 and rheumatoid arthritis: When we incubated PBMCs from patients with RA indirectly with FLSs using transwell inserts, the expression of IL-1β, IL-6, and IL-8 was higher in FLSs exposed to PBMCs from patients with moderate RA than in FLSs exposed to PBMCs from healthy controls (n = 3 per groups; p < 0.05; Figure 4A,B).