Anti-MCV antibodies are member of ACPA family, a group of the so called antibodies to citrullinated protein/peptide antigens.MCV is the abbreviation for Mutated Citrullinated Vimentin. Vimentin itself is a protein of the cytoskeleton of several cells like mesenchymal cells and osteocytes. It is used as a marker for soft tissue tumors.

Since 1994 vimentin (first known as Sa antigen) has been mentioned in the context of RA. Vimentin is an omnipresent citrullinated protein, which was observed in the rheumatoid synovial tissue of RA patients. Antibodies against citrullinated vimentin show the highest specificity in the diagnosis of RA. The citrullination of vimentin is caused by PAD (peptidylarginine deiminase) which induces changes in the protein structure and increases potential epitopes - targets for the autoantibodies coherent to RA.