Temporal Association Between PLA2R Antibodies and Clinical Outcomes in Primary Membranous Nephropathy

INTRODUCTION: Autoantibodies to M-type phospholipase A2 receptor (aPLA2R) are seen in two-thirds of patients with primary membranous nephropathy (PMN) and are associated with disease activity. However, the precise temporal dynamics between the presence and amount of aPLA2R in circulation, as well as the clinical activity, are not known. We evaluated the temporal association between disease activity and serum aPLA2R during and after treatment in PMN. METHODS: The study included all patients with PMN and elevated aPLA2R who were started on immunosuppressive therapy for persistent nephrotic syndrome at a single center between December 2014 and December 2015. Serum samples were tested for aPLA2R at baseline and at monthly intervals for 6 months. Clinical details were collected monthly for 9 months. Serological remission was defined as negative aPLA2R in 2 consecutive samples. Clinical remission was defined by standard criteria. RESULTS: A total of 30 patients with PMN were studied. Of these, 28 (93%) had elevated levels at baseline, whereas 2 (7%) became positive after 1 month. The mean age was 33.2 ± 1 (range, 13−52) years. Median baseline aPLA2R titer was 163.41 (range, 70−291.01) RU/ml. A total of 24 patients (80%) achieved serological remission by 6 months. Among all the serological responders, 54% had achieved negative aPLA2R by the end of the first month. Clinical remission was observed in 20 patients (67%). Serological and clinical remission were noted at 2.7 ± 1.71 and 5.05 ± 2.64 months, respectively. CONCLUSION: In patients with aPLA2R-associated PMN, reduction in circulating aPLA2R precedes clinical remission. Persistence of aPLA2R at the end of therapy is associated with clinical resistance.