HSPA1A and rheumatoid arthritis: Pre-clinical observations have proven that artificial immunization with highly conserved bacterial and/or murine Hsp70 peptides could be regarded as a potential treatment target for rheumatoid arthritis (RA) via induction of antigen-specific Treg cells (Wendling et al. 2000; van Eden et al. 2005; Wieten et al. 2009; van Herwijnen et al. 2012; van Eden et al. 2013; Tukaj and Kaminski 2019).