HSPD1 and rheumatoid arthritis: Six of these proteins corresponded to already-described RA antigens – heterogeneous nuclear ribonucleoprotein A2/B1 [26,27], aldolase [28], α-enolase [29], calreticulin [30,31], BiP [32,33] and HSP60 [34,35] – demonstrating the validity of our methodology approach.