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Abstract: FR-PO1093

Glomerular Phospholipase A2 Receptor Antigen in Lupus Membranous Nephritis

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Nakata, Mayumi, St. Marianna University Hospital, Kawasaki, Japan
  • Suzuki, Tomo, St. Marianna University Hospital, Kawasaki, Japan
  • Watanabe, Shiika, St. Marianna University Hospital, Kawasaki, Japan
  • Ichikawa, Daisuke, St. Marianna University Hospital, Kawasaki, Japan
  • Koike, Junki, Kawasaki Municipal Tama Hospital, Kawasaki, Japan
  • Shibagaki, Yugo, St. Marianna University Hospital, Kawasaki, Japan
Background

Phospholipase A2 receptor (PLA2R) is the major pathogenetic antigen in idiopathic membranous nephropathy (iMN). Anti-PLA2R antibody is detected in approximately 70% with iMN and glomerular PLA2R expression by immunofluorescence and serum PLA2R antibody are often observed. Its prevalence and characteristics in lupus membranous nephritis remains to be undetermined.

Methods

We conducted a cross-sectional study at two-centers in Japan, including patients whose renal biopsies show ISN/RPS Class V lupus nephritis, between May 25, 2012 to March 31, 2018. We performed immunofluorescence analysis of frozen section for PLA2R expression using anti-PLA2R antibody. We evaluated the clinical and pathological features between positive-PLA2R group (PLA2R-P) and negative group (PLA2R-N) and checked the serum anti-PLA2R antibody only in PLA2R-P.

Results

We analyzed the glomerular expression of PLA2R Ag in 23 patients, as many as 5 patients had positive glomerular PLA2R antigen expression. As shown in the Table, we compared the characteristics between PLA2R-P and PLA2R-N. The age and the duration from the diagnosis of SLE to biopsy were higher in PLA2R-P, but not significantly. Although the difference in the levels of proteinuria was not significant, the level of serum total protein was significantly lower in PLA2R-P. The levels of C3 and C4, and the intensity of glomerular IgG1 deposition were significantly higher in PLA2R-P. On the other hand, serum anti-PLA2R antibody level are all normal in the PLA2R-P.

Conclusion

Significant proportion of class V lupus nephritis showed positive PLA2R in kidney specimen in spite of absence of circulating anti-PLA2R antibody. Cases with positive PLA2R had significantly lower serum total protein and higher complement levels. Higher complement and proteinuria level may indicate poor activity of lupus nephritis and more phenotypical similarity to iMN.

Characteristics of lupus nephritis ClassV.