Antibodies to Modified Citrullinated Vimentin (Anti-MCV)

Antibodies to modified citrullinated vimentin (anti-MCV) are autoantibodies directed against an altered form of the body's own vimentin protein. They belong to the anti-citrullinated protein antibody (ACPA) family and may be detected in patients with rheumatoid arthritis (RA).

Vimentin is a cytoskeletal intermediate filament protein characteristic of cells of mesenchymal origin, including synovial fibroblasts and macrophages. Citrullination is the enzymatic conversion of arginine residues into citrulline after protein synthesis. Under certain conditions, citrullinated vimentin becomes an autoantibody target. MCV is the modified citrullinated antigen used in the corresponding laboratory test; it should not be regarded as the only natural form of vimentin in RA.

Diagnostic Value

Serological tests complement assessment of joint symptoms. Anti-MCV may be useful in selected cases, including early arthritis, but sensitivity and specificity depend on the method, cutoff and comparison group. Claims of universal 98% specificity, 70–84% sensitivity or unconditional superiority of combining anti-MCV with anti-CCP cannot be applied to all patients and assays. In some studies, anti-MCV was less specific than anti-CCP.

A positive result supports a suspicion of RA in the appropriate clinical setting but does not independently confirm the diagnosis. A negative result does not exclude the disease. Anti-MCV may also occur in systemic lupus erythematosus, Sjögren syndrome, psoriatic arthritis and other conditions.

Early Detection and Criteria

RA-associated autoantibodies sometimes appear before symptoms. However, a fixed period of 10–15 years cannot be used to predict an individual's course, and positivity does not mean RA will inevitably develop. For an asymptomatic person with a positive result, the clinician determines the need for further assessment based on history and other findings.

The 2010 ACR/EULAR criteria consider RF or ACPA together with joint involvement, symptom duration and inflammatory markers. This does not specifically mandate anti-MCV or allow diagnosis on serology alone. RF and anti-CCP are widely used in clinical practice; a specialist decides whether additional anti-MCV testing is needed.

Results are interpreted alongside examination, ESR/CRP, other antibodies and imaging. Negative antibodies must not delay rheumatology assessment when persistent joint swelling is present.