Urine β2-microglobulin is associated with clinical disease activity and renal involvement in female patients with systemic lupus erythematosus

摘要

Objective: We investigated the association of serum and urine b2-microglobulin (b2MG) with renal involvement and clinical disease activity in systemic lupus erythematosus (SLE).Methods: Sixty-four female patients with SLE were enrolled. We assessed SLE disease activity (SLEDAI)-2K and measured serum and urine b2MG levels, as well as complement (C3 and C4) and anti-dsDNA levels. According to the SLEDAI scores, two groups were categorized: low (0-5 of SLEDAI) and high (6-19 of SLEDAI) disease activity groups. The presence of renal involvement was determined by renal SLEDAI score. Statistical analysis was performed using Spearman's correlation analysis, Mann-Whitney U test, multivariate regression analysis, and logistic regression analysis.Results: Urine b2MG levels were significantly different between low and high SLEDAI groups (p=0.001), but not for serum b2MG levels (p=0.579). Patients with renal involvement showed higher urine b2MG levels compared to those without renal involvement (p<0.001), but again there was not a difference in serum b2MG levels (p=0.228). Urine b2MG was closely associated with SLEDAI (r=0.363, p=0.003), renal SLEDAI (r=0.479, p<0.001), urine protein/Cr (r=0.416, p=0.001), and ESR (r=0.347, p=0.006), but not serum b2MG (r=0.245, p=0.051). Urine b2MG level was identified as a surrogate for renal involvement (p=0.009, OR=1.017, 95% CI 1.004-1.030) and overall disease activity (p=0.009, OR=1.020, 95% CI 1.005-1.036).Conclusions: We demonstrated that urine b2MG levels are associated with renal involvement and overall clinical disease activity in SLE. Lupus (2014) 23, 1486-1493.