IL6 and rheumatoid arthritis: Pharmacological blockade of the cascade is accompanied by a substantial and consistently reproducible reduction in the production of IL-6 and IL-8—both at the level of secretion in MH7A cells (g = –5.29 and –6.47; see Figure 4A,D) and in terms of expression in primary RA-FLSs activated by Semaphorin-5A (g = –11.15 and –4.10; Figure 4B,F).