The association of serum anti-PLA2R antibody and glomerular PLA2R antigen staining with clinical manifestations and outcomes in membranous nephropathy

Background: Phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN) was manifested as seropositive for PLA2R antibodies (SAb) and/or glomerular PLA2R antigens' (GAg) deposits. According to the test of SAb and GAg, PLA2R-associated MN can be divided into SAb + /GAg-, SAb-/GAg + , and SAb + /GAg + groups. The clinical characteristics and outcomes of the three groups need to be further evaluated.

Methods: 184 PLA2R-associated MN patients were enrolled. SAb was measured by enzyme-linked immunosorbent assay with a cut-off value of 14 RU/mL. GAg was detected by immunofluorescence using a paraffin section of renal biopsy samples. Clinical characteristics and the decline of eGFR were compared among the 3 groups.

Results: There were 33 SAb + /GAg-, 46 SAb-/GAg +, and 105 SAb + /GAg + PLA2R-associated MN patients reviewed. Clinical characteristics, such as the level of proteinuria, serum albumin, as well as eGFR, were comparable between the SAb + /GAg- and SAb + /GAg + patients. While SAb-/GAg + patients exhibited mild clinical manifestations as evidenced by higher serum albumin (P < 0.001) and lower proteinuria (p = 0.049) compared with SAb + /GAg + patients. After 21.96 ± 7.39 month follow-up, the eGFR decrease was no difference between the SAb + /GAg- and SAb + /GAg + patients. SAb-/GAg + patients had a lower rate of the > 20% eGFR decline as well as a 50% eGFR decline compared with the SAb + /GAg + patients (10.87% vs 30.48%, p = 0.013; 0.00% vs 4.76%, p = 0.324).

Conclusions: Our study showed that the clinical manifestations of SAb + /Gag- patients were the same as those of double-positive patients, while SAb-/GAg + patients exhibited mild clinical manifestations and slower eGFR decline compared to the double-positive patients.