Elevation of serum ferritin levels as a marker for active systemic lupus erythematosus

To determine the clinical relevance of serum levels of ferritin in patients with systemic lupus erythematosus (SLE) vs. controls, we assessed the correlations between such levels and clinical disease activity, anti-DNA antibody titer, and serum levels of complement.

We evaluated 36 patients (3 males and 33 females) with SLE, including 21 patients with active disease. A total of 52 patients (3 males and 49 females) with rheumatoid arthritis (RA) served as controls. In a further study for reproducibility, 15 SLE and 21 RA patients were examined. Serum ferritin levels were measured by a 2-site radioimmunometric assay. Serum levels of C-reactive protein (CRP) were measured semiquantitatively by immunoprecipitation or quantitatively by laser immunonephelometry. Anti-DNA antibody was measured by the Farr assay. CH50 was measured by the hemolytic activity method.

The SLE patients exhibited higher serum levels of ferritin and lower serum levels of CRP than the RA patients. Serum levels of ferritin at the active stage of SLE exceeded those at the inactive stage. The levels of serum ferritin in SLE were positively correlated with the anti-DNA antibody titer and negatively correlated with CH50 values.

Serum levels of ferritin appear to provide a useful marker of disease activity in SLE patients.