Serum ferritin level correlates with SLEDAI scores and renal involvement in SLE

Ferritin is an acute-phase reactant that is elevated in various autoimmune disorders. Serum ferritin levels have been positively correlated with disease activity scores of rheumatoid arthritis and systemic lupus erythematosus (SLE). Further, enhanced levels of ferritin have also been reported in lupus nephritis. However, there are no reports from the Indian subcontinent.

Seventy-six female SLE patients, diagnosed on the basis of revised ACR criteria, and 50 healthy females, age matched from similar geographical areas, were enrolled in the present study. Serum levels of ferritin, IFN-α and IL-6 were quantified by enzyme-linked immunosorbent assay (ELISA). Clinical, biochemical, serological and other markers of disease activity (C3, C4 and anti-dsDNA) were measured by standard laboratory procedure.

Serum ferritin levels were significantly higher in SLE patients compared to healthy controls (p < 0.0001). Ferritin levels positively correlated with SLE Disease Activity Index (SLEDAI) (p = 0.001, r = 0.35), anti-dsDNA (p = 0.001, r = 0.35), IFN-α (p < 0.0001, r = 0.51) and IL-6 (p < 0.0001, r = 0.65) and negatively correlated with C3 (p = 0.0006, r = -0.38) and C4 (p = 0.01, r = -0.28). Interestingly, serum levels of ferritin were positively associated with proteinuria (p = 0.001, r = 0.36), serum urea (p = 0.0004, r = 0.39) and serum creatinine (p = 0.0006, r = 0.38).

Serum ferritin is an excellent marker of disease activity and renal dysfunction in SLE.