Objective: To clarify the clinical significance of the antibody against v-raf murine sarcoma viral oncogene homologue B1 (BRAF) in the diagnostic practice of rheumatoid arthritis (RA).
Methods: In the study, 112 patients with RA, 112 patients with other rheumatic diseases,and 73 healthy individuals were recruited . With recombinant human BRAF protein as antigen, we examined the level of anti-BRAF antibody in all the patients by enzyme-linked immunosorbent assay(ELISA), The clinical data of the RA patients were collected simultaneously, and analysed statistically by using SPSS 13.0.
Results: The positive rate of anti-BRAF antibody was 53.6% in the RA patients, which was significantly higher than that of the normal control group (4.1%,P<0.01)and other rheumatic diseases groups (P all<0.01)except osteoarthritis group. The titer of anti-BRAF antibody was also notably higher in the patients with RA than in other rheumatic diseases and normal control groups(P all <0.01).The diagnostic sensitivity and specificity of anti-BRAF antibody for RA were 53.6% and 84.3% respectively. The positive rate of anti-BRAF antibody in rheumatoid factor, anti-cyclic citrullinated peptide antibody, antikeratin antibody,antiperinuclear factor negative groups were 52.6%,38.2%, 30.3% and 31.0%respectively. It showed significant negative correlation between the titer of anti-BRAF antibody and patient's age, disease duration and the level of CRP.
Conclusion: The anti-BRAF antibody contributes to the diagnosis of RA, and may act as a supplement of other autoantibodies.