Association of autoantibodies to filaggrin with an active disease in early rheumatoid arthritis

Objective-To evaluate the clinical significance of antifilaggrin antibodies (AFA) measured by an enzyme linked immunosorbent assay (ELISA) in serial specimens from patients with recent onset rheumatoid arthritis (RA). Methods-Filaggrin was purified from human skin and used as an antigen in ELISA. The AFA test was applied to five serial specimens from 78 patients with recent onset RA followed up for three years. Rheumatoid factor (RF) had been measured earlier from the same samples by quantitative immunoturbidimetry. Results-The mean AFA level was highest at entry (54% positive), followed by a statistically significant decline at six months and a slight increase at three years. AFA were persistently positive in 23 patients and persistently negative in 28 patients. Eleven of the latter patients were persistently negative for RF. At study entry AFA levels correlated to some degree with RF levels. in general, raised AFA levels at entry were associated with an active and treatment resistant disease, but they did not predict radiological progression. Conclusions-The test for AFA has potential for an additional immunological test for RA.