IL-10 is a cytokine known to inhibit inflammatory cytokines. To determine its role in the pathogenesis of systemic lupus erythematosus (SLE), the presence of anti-IL-10 antibody is required to be examined. Although antibodies against cytokines are known to be present in SLE, no studies have determined the role of IL-10, particularly in Japanese patients. We assayed anti-IL-10 antibody in SLE and examined the clinical significance.
We performed a retrospective study of 80 Japanese patients with SLE. Sixteen scleroderma patients, 19 rheumatoid arthritis (RA) patients, 23 Behcet’s disease patients, and 23 healthy subjects were selected as control groups. Clinical information was abstracted from medical records. Anti-IL-10 antibody level was determined with an ELISA.
With the cutoff established as serum absorbance +2 SDs (OD 0.729) in healthy subjects, we defined any sample above this cutoff as anti-IL-10 antibody-positive. Fourteen patients with SLE (17.5%) were found to be anti-IL-10 antibody positive. Absorbance was significantly higher in serum from patients with SLE and RA than in healthy individuals. In SLE, patients with low complement values were significantly more common in the antibody-positive group. Serum IgG levels were significantly higher in the antibody-positive group. In multivariable analysis, high level of serum IgG is associated with anti-IL-10 antibody positive.
The present study found that anti-IL-10 antibody is present in SLE and related to clinical parameters. These results suggest that the presence of anti-IL-10 antibody was associated with high level of serum IgG, but is not associated with disease activity in patients with SLE.