To investigate the clinical significance of perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA) in patients with systemic lupus erythematosus (SLE).

This retrospective study included 120 SLE patients. All patients were divided into group p-ANCA+ and group p-ANCA−. Demographic characteristics, clinical symptoms, autoantibodies, laboratory tests and renal pathology were compared between these two groups.

Among 120 patients, 45 (37.5%) patients were p-ANCA+ and 75 (62.5%) patients were p-ANCA−. The occurrence of lupus nephritis was significantly higher in group p-ANCA+ (P = 0.046). For autoantibodies, the occurrences of anti-dsDNA, anti-nucleosome and anti-histone were significantly higher in group p-ANCA+ (P < 0.001, P = 0.004 and P = 0.006, respectively). Titers of anti-dsDNA antibody, erythrocyte sedimentation rate (ESR), serum beta-2-microglobulin (β2-MG) and systemic lupus erythematosus disease activity index (SLEDAI) were higher in group p-ANCA+ (P < 0.001, P = 0.021, P < 0.001 and P = 0.005, respectively), while albumin was significantly lower than p-ANCA− group (P = 0.012). There were no differences in the classification of lupus nephritis, activity index and chronicity index. p-ANCA correlated with lupus nephritis, anti-dsDNA antibody, anti-nucleosome antibody and anti-histone antibody, and also disease activity markers, such as titers of anti-dsDNA antibody, ESR, albumin, serum β2-MG and SLEDAI.

The appearance of p-ANCA in SLE indicated high probability of lupus nephritis and more severe condition.