Similarly, the level of the cytokines: IL-8 (Fig. 2B), RANTES (Fig. 2C), IL-6 (Fig. 2D) and TNFα (Fig. 2E) were significantly elevated, suggesting that the up-regulation of TREM1 correlates with activation of PMNs in RA patient specimens and demonstrating that TREM1 increased expression is also linked to an increase in its activity. Here, TREM1 is linked to rheumatoid arthritis.