Association of antiphospholipid antibodies with clinical activity and renal pathological activity in patients with lupus nephritis

Objectives This study aimed to investigate the association of antiphospholipid antibodies (aPL) with clinical activity and renal pathological activity in patients with lupus nephritis (LN). Methods Levels of anticardiolipin () antibodies, anti-beta 2-glycoprotein I (anti-beta 2-GPI) antibodies and lupus anticoagulant (LAC) were measured, and other clinical and pathological data were also obtained during the same period before renal biopsy. Results A total of 83 patients with LN were included in this study, 40 patients (48.2%) in the s positive group and 43 patients in the aPL negative group. LN patients with positive aPL had significantly higher SLEDAI (p = 0.012), more hematuria (p = 0.043), lower serum C3 (p = 0.003) and C4 (p = 0.014), and a higher pathological activity index (p = 0.012), more micro-thrombosis (p = 0.046) and more C3 deposits (p = 0.038) in the glomerulus than patients with negative aPL The level of IgG- was significantly correlated with SLEDAI and serum level of C3 (r = 0.44, p < 0.001; r = -0.39, p = 0.003, respectively). The level of IgM- was significantly correlated with SLEDAI, and serum levels of C3 and C4 (r = 0.27, p = 0.014; r = -0.22, p = 0.041; r = -0.23, p = 0.035, respectively). Conclusions Our work suggests that aPL, especially, are correlated with both clinical activity and renal pathological activity in patients with LN.