Anti-nucleosome antibodies: A potential surrogate marker for renal affection in lupus patients with insignificant proteinuria

BackgroundLupus nephritis (LN) is a serious manifestation of systemic lupus erythematosus (SLE). Clinical renal involvement is present in about two-thirds of lupus patients and more patients would have morphologic evidence of renal disease without clinical manifestations.Aim of the workTo investigate serum anti-nucleosome antibodies role as a biomarker for renal affection in lupus patients with insignificant proteinuria.Patients and methodsTwenty-four lupus patients with proteinuria <500 mg/d (group-A), 30 patients with established lupus nephritis (group-B) and 15 controls were included. Systemic lupus erythematosis disease activity index (SLEDAI), anti-nucleosome, anti-dsDNA antibodies and renal biopsy were assessed in all patients.ResultsSerum anti-nucleosome antibodies were significantly higher in all lupus patients than control (P < 0.001) and showed significant positive correlation with SLEDAI score. SLE patients with positive anti-dsDNA antibody had more active disease by SLEDAI and higher levels of anti-nucleosome antibodies than those with negative anti-dsDNA antibodies. In both studied groups, serum anti-nucleosome antibodies were significantly higher in patients with class II LN than the control and in class III LN than in class II LN (P < 0.001). Yet, in both groups, anti-nucleosome was not useful in differentiating active from chronic renal affection.ConclusionSerum levels of anti-nucleosome antibodies are associated with active lupus disease and correlate with the degree of renal affection. In patients with insignificant proteinuria, serum levels of anti-nucleosome antibodies were elevated and were related to the degree of renal affection. Anti-nucleosome antibodies may be used as a surrogate marker for early renal affection in lupus patients with insignificant proteinuria.