Analysis of predictive factors for immunosuppressive response in anti-phospholipase A2 receptor antibody positive membranous nephropathy

BACKGROUND: Serum anti-phospholipase A2 receptor (PLA2R) antibody was correlated with disease activity of membranous nephropathy(MN). The predictive value of antibody titer changes on immunosuppressive response remains unknown. We investigated predictive value of dynamic change of anti-PLA2R antibody and 24-h urine protein (24hUP) for clinical response of MN. METHODS: This was a retrospective cohort study including 47 Chinese MN patients with positive anti-PLA2R antibody in a tertiary referral hospital between January 2012 and March 2014. Patients received cyclophosphamide (CTX, n = 23), or cyclosporine (CYA, n = 24) regimen, respectively. We monitored serum anti-PLA2R titer and 24hUP at one, three and six-month follow-up. RESULTS: At baseline, total patients were 42 ± 14 years old with 29/18 male/female ratio. The median 24hUP was 5.80(3.56,9.41) g/d. The median baseline anti-PLA2R antibody titer was 66.4(31.9, 188.0) RU/mL. Baseline 24hUP and eGFR between subgroups were not significantly different. The differences of relative reduction between antibody titer and 24hUP at one month were statistically significant (CTX group 94.2% vs. 46.8%, P < 0.001; CYA group 54.6% vs. 4.6%, P = 0.04). Only in CTX group, the relative reduction of 24hUP at one month was correlated with composite remission at six-month(P = 0.03). Area under the curve of 24hUP relative reduction in CTX group at one-month for predicting composite remission at six months was 0.85(95%CI 0.65~1.05, P = 0.04). The cutoff value of one-month’s 24hUP relative reduction for predicting six-month’s composite remission in CTX group was 15.3%, with high sensitivity (83.3%) and specificity (100%). CONCLUSIONS: Compared with relative reduction of antibody titer, relative reduction of 24hUP at one-month follow-up in CTX group had a better predictive value for six-month’s composite remission.