To evaluate the significance of the combination of rheumatoid factor (RF) and anti-filaggrin antibodies (AFAs) in the diagnosis of rheumatoid arthritis (RA).
Sera from 266 RA patients and 186 controls were studied. RF and some kinds of AFAs (including antikeratin antibodies, anti-perinuclear factor and anticyclic citrullinated peptide antibodies) were detected using immunofluorescence and ELISA respectively. The distributions of these antibodies were compared to determine the significance of the combination of RF and AFAs.
The sensitivity and secificity of RF for the diagnosis of RA were 65.8% and 81.8% respectively, as compared with those of anti-CCP or RF positive were 86.5% and 80.6% respectively. Only a slight change was found in the secificity and negative predictive value between them. RF could not be detected in 91 patients while 64.8% of them could be found to have at least one kind of AFAs.
AFAs, particular anticyclic citrullinated peptide antibodies, could be helpful for the diagnosis of RA especially in RF-negative patients.