Diagnostic Value of Anti-Fibrinogen Citrullinated Peptide in Rheumatoid Arthritis.

OBJECTIVE: To determinate the diagnostic value of an antibody against a citrullinated fibrinogen peptide in Cuban patients with rheumatoid arthritis, using an enzyme immunasay.

MATERIALS AND METHODS: A citrullinated peptide of fibrinogen designed by informatics prediction was synthesized and used in an enzyme immunoassay. The participants were 81 patients with early disease, 81 patients with established disease, 58 patients with other rheumatic and inflammatory diseases, and 43 healthy individuals. Anti- citrullinated fibrinogen peptide, anti-mutated citrullinated vimentin, anti second generation citrullinated peptides and rheumatoid factor antibodies were determined by enzyme-linked immunosorbent assay.

RESULTS: Determination of anti-citrullinated peptide of fibrinogen antibodies by the designed enzyme immunoassay showed the best diagnostic value in early rheumatoid arthritis patients, with the highest value sensitivity (84%), negative predictive value (85%), Youden index (0.73%) and area under the receiver operating curve (0.9192). Specificity (89%) and positive predictive value (88%) were higher than rheumatoid factor, similar to anti- mutated citrullinated vimentin, but lower than second generation anti-citrullinated peptides assay. The positivity of C-reactive protein was associated with the presence of anti- citrullinated fibrinogen peptide antibodies and the titres of these antibodies correlated with clinical activity in early disease.

CONCLUSIONS: The immunoassay designed with a citrullinated fibrinogen peptide has a high diagnostic value and can identify patients with greater clinical activity in early rheumatoid arthritis.