While the citrullination of CNS proteins has been noted
in MS, the development of antibodies to citrullinated proteins
is relatively specific to rheumatoid arthritis (RA), which is
a chronic inflammatory disease and often leads to peripheral
joints involvement and extra-articular manifestations
[8]. Anticyclic citrullinated peptide (anti-CCP), an antibody
against citrullinated proteins, is frequently used as diagnostic
test for RA, with a specificity of 96–100% and a sensitivity
of 40–85% [9].