CXCL8 and rheumatoid arthritis: Importantly, lTSLP mRNA levels in patients with RA were positively correlated with IL-1β mRNA levels (r = 0.7487, P < 0.0001), IL-6 mRNA levels (r = 0.6945, P < 0.0001), and IL-8 mRNA levels (r = 0.3453, P = 0.0039), respectively (Figure 3B).