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Abstract: TH-PO1001

Determination of Anti-PLA2R and Anti-THSD7A Antibodies in Brazilian Patients with Idiopathic and Lupus Membranous Nephropathy

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Battaini, Ligia Costa, University of Sao Paulo Brazil, Quito, Ecuador
  • Larrea, Pamela Belen, University of Sao Paulo Brazil, Quito, Ecuador
  • Marçal, Lia Junqueira, Universidade de Sao Paulo, Sao Paulo - SP, Brazil
  • Jorge, Lectícia, University of São Paulo, São Paulo, Brazil
  • Antonangelo, Leila, Universidade de Sao Paulo, Sao Paulo - SP, Brazil
  • Malheiros, Denise M., Univ of Sao Paulo, Sao Paulo, Brazil
  • Yu, Luis, University of Sao Paulo School of Medicine, Sao Paulo, Brazil
Background

Membranous Nephropathy (MN) is a common cause of nephrotic syndrome in adults. In Brazil, it is the second most frequent cause of glomerulopathies. Incidence variations in between the various studies may reflect patterns of biopsy indication in different countries however, it may also be related to socioeconomical, ethnical or environmental characteristics. In the past years, the role of anti-phospholipase A2 (anti-PLA2R) receptor autoantibodies and the antibody against THSD7A (thrombospondin type 1 domain containing protein 7A) in the pathogenesis of idiopathic MN were described. The determination of these serum and renal tissue antibodies have not yet been performed in the Brazilian population.

Methods

Blood samples were collected from 26 patients diagnosed with MN and 13 patients with Lupus Membranous Nephropathy (LMN), confirmed by renal tissue biopsy (OM and IF). The anti-PLA2R antibody was measured by the ELISA and IIFT techniques and antibodies against THSD7A by IIFT. In addition, routine tests of renal function and proteinuria were also collected. Patients will be followed and evaluated after 6 months and 1 year of the initial consultation.

Results

All 13 patients with LMN were negative for anti - PLA2R and anti - THSD7. A total of 26 patients with MN tested negative for anti - THSD7A. Out of 26 patients, 13 (50%) were anti-PLA2R negative by both ELISA and IIFT. On the other hand, 10 patients (38.4%) were positive by both methods and 3 patients were positive only by IIFT and had intermediate titers by ELISA method, resulting in 13 positive patients (50%). Proteinuria levels in ELISA and IIFT negative patients were 1.98g / vol, 6.7g / vol for ELISA and IIFT positive patients and 2.96g / vol for intermediate ELISA and IIFT positive patients, respectively. In this sample, there was a positive correlation between the anti - PLA2R titers and the levels of proteinuria.

Conclusion

In this Brazilian population of MN patients, there was a 50% positivity for anti - PLA2R. The IIFT technique was more sensitive than the ELISA test. No patient was positive for anti-THSD7A. All patients with LMN were negative for both antibodies.There was a positive correlation between the anti - PLA2R antibodies serum levels and the degree of proteinuria.

Funding

  • Government Support - Non-U.S.