HSPA1A and rheumatoid arthritis: Heat shock proteins were also found to be present as extracellular proteins [5, 6], and concentrations of these have been found to vary in many conditions, including HSPB1 and HSPA1A in cancer [7, 8, 9], cardiovascular disease [10], HSPB1 in atherosclerosis [11] and HSPA1A in rheumatoid arthritis [12].