Rheumatoid arthritis: an antigenic chameleon

For those who are particularly interested in the autoimmune response in RA, we have to realise that we are engaged with a true chameleon. Since the discovery more than 15 years ago of humoral autoimmune reactivities to epitopes containing the unusual amino acid citrulline, 1 many new autoimmune targets have been discovered and, even more important, also different post-translational modifications to push their antigenic properties. [...]carriers of distinct HLA alleles coding for the so called shared epitope (particularly HLA-DR*0401) have the highest risk for the development of ACPA, and subsequently RA, especially when they are smokers.