Measurement of interleukin-1 receptor antagonist in patients with systemic lupus erythematosus could predict renal manifestation of the disease.

Interleukin-1 receptor antagonist (IL-1Ra) is a good indicator of disease activity in patients with systemic lupus erythematosus (SLE). Glucocorticosteroids are the most frequently used drugs in SLE. Our goal was to compare IL-1Ra activity in SLE patients with and without renal involvement and to determine the effect of different dosage of glucocorticosteroids used in 17 patients with active SLE without nephritis, 7 patients with inactive lupus nephritis (LN), and 8 patients with active LN, along with 10 healthy controls. IL-1Ra levels were measured in the serum of SLE patients by Human Luminex [100] analyzer. Both in patients with active SLE without nephritis and in patients with LN, serum levels of IL-1Ra (p<0.001) were significantly higher compared with those in the controls. IL-1Ra was significantly higher in patients with active LN than in patients with inactive LN (p = 0.028). The use of methylprednisolone was significantly higher in the active LN group compared with the inactive LN group (p = 0.013). SLE patients with higher IL-1Ra are at lower risk for developing nephritis. The higher doses of glucocorticosteroids needed in active LN could be due to steroid resistance and IL-1Ra polymorphism. Measurement of IL-1Ra levels in SLE patients could help to predict future renal involvement. Copyright 2010 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.