Antifilaggrin antibodies in recent-onset arthritis

We evaluated the sensitivity and prognostic value of an enzyme-linked immun osorbent assay (ELISA) for the measurement of antifilaggrin antibodies (AFA ), using filaggrin purified from human skin as an antigen. The AFA test was applied to a series of 306 patients with various recent-onset inflammatory joint diseases. The results were compared to those of the conventional imm unofluorescence tests for antikeratin antibody (AKA) and antiperinuclear fa ctor (APF) and of the rheumatoid factor (RF) tests from a previous study. T here was a very good agreement between the results of the tests for APF and AFA (kappa-value 0.79 in patients with peripheral poly/oligoarthritis). Th e agreement between the tests for AKA and AFA was significant but less pron ounced (kappa-value 0.50). The AFA test detected 10/22 of the RF-negative e rosive cases, particularly those with a large number of erosive joints. Thu s, the test for AFA supplements RF in the prediction of erosiveness.