Association Between Antiphospholipid Antibodies And Factor Bb In Lupus Nephritis Patients With Glomerular Microthrombosis

Background and purpose The mechanism of glomerular microthrombosis (GMT) in patients with lupus nephritis (LN) is largely unknown. The aim of this study is to investigate the association between antiphospholipid antibodies (aPLs) and factor Bb in LN patients with GMT. Methods Patients with biopsy-proven LN hospitalized from July 2015 to July 2018 in our hospital were selected for this study. Levels of lupus anticoagulant (LAC), anticardiolipin antibodies (aCLs), anti-beta 2-glycoprotein I (anti-beta 2-GPI) antibodies and factor Bb were measured, and other clinical and pathological data were also obtained during the same period before renal biopsy. Results A total of 25 LN patients with GMT and 76 LN patients without GMT were included in this study. In LN patients with GMT, the presence of anti-beta 2GPI and LAC were both significantly higher than in those without GMT (P P = .039, respectively). The level of factor Bb was also higher in LN patients with GMT than in those without GMT (P = .021). In the correlation analysis, Bb level was positively correlated with serum creatinine (r = 0.28, P = .014), activity index (r = 0.24, P = .021) GMT (r = 0.65, P < .001) and IgG-anti-beta 2GPI (r = 0.771, P < .001). Conclusions Our work suggests that aPLs, especially IgG-anti-beta 2GPI, may play a role in the progress of GMT, and this process might involve alternative complement activation.