Raised serum level of APRIL in patients with systemic lupus erythematosus: correlations with disease activity indices

The aim of the present study is to assess serum APRIL levels in SLE patients versus rheumatoid arthritis (RA) patients and normal control and to correlate serum APRIL levels in SLE patients with disease activity indices. Serum APRIL levels was measured in 40 SLE patients, 20 patients with RA and 20 healthy volunteers who served as control group. Disease activity in SLE patients was assessed by the British Isles Lupus Assessment Group (BILAG) index and SLE disease activity index (SLEDAI), and results were correlated with serum APRIL levels. Significantly higher serum APRIL levels was observed in SLE patients compared to RA patients and normal controls (p=0.003 and p < or = 0.001, respectively). Positive correlations were found between serum APRIL levels and total BILAG index (r=0.486 and p=0.001), BILAG musculoskeletal score (r=0.848 and p < or = 0.001) and BILAG cardiorespiratory score (r=0.326 and 0.04). Serum APRIL was higher in SLE patients compared to RA patients and normal control subjects and positively correlates with BILAG index and higher levels may be associated with musculoskeletal manifestations of the disease. APRIL antagonism could be a potential therapeutic target in SLE.