Autoantibodies against phospholipase A2 receptor in Brazilian patients with glomerular diseases

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NEPHROLOGY - ORIGINAL PAPER

Autoantibodies against phospholipase A2 receptor in Brazilian patients with glomerular diseases Cícero de Oliveira Santos Neto1 · Michelle T. Passos1 · Danilo E. Fernandes1   · Sonia K. Nishida1 · Luís Eduardo Coelho Andrade2,3 · Gianna Mastroianni Kirsztajn1 Received: 28 June 2020 / Accepted: 12 October 2020 © Springer Nature B.V. 2020

Abstract Background  Recently, great progress has been made in understanding the pathogenesis of membranous nephropathy (MN) with the discovery of autoantibodies (Abs) to M-type phospholipase A2 receptor (PLA2R) in serum and in immunocomplexes deposited in glomerulus in most adult patients with primary MN. Objective  To evaluate the diagnostic performance of anti-PLA2R in Brazilian patients with MN, as well as to verify the possible association of anti-PLA2R serum levels with disease activity. Methods  117 patients with glomerular diseases confirmed by renal biopsy underwent routinely clinical and laboratory evaluation (serum creatinine and albumin, 24-h proteinuria, urinalysis, tests for etiological investigation) and determination of serum anti-PLA2R by ELISA. Results  67.5% of the patients had MN, 9.4% focal segmental glomerulosclerosis, 7.7% lupus nephritis class V and 15.4%, other proteinuric glomerular diseases. The mean level of glomerular filtration rate (estimated by the CKD-EPI formula) was 79.43 mL/min (12.00–151.20 mL/min), 24 h proteinuria of 2.89 g (0–14.90 g), serum albumin of 3.79 g/dL (1.20–4.80 g/ dL). Anti-PLA2R was detected in 27 patients, all with active MN, being 26 primary and 1 secondary MN. Sensitivity and specificity rates for the test were 60.5–94.7%, and positive (PPV) and negative (NPV) predictive values were 92.9 and 67.9%, respectively. Conclusions  Anti-PLA2R showed high specificity and PPV for the diagnosis of primary MN in Brazilian patients. There was a strong correlation between disease activity and positive anti-PLA2R. This biomarker represents an important diagnostic tool for primary MN and may contribute to the monitoring of disease activity in such patients. Keywords  Glomerulonephritis · Membranous nephropathy · Anti-PLA2R · Biomarkers · Brazil

Introduction

Electronic supplementary material  The online version of this article (https​://doi.org/10.1007/s1125​5-020-02682​-w) contains supplementary material, which is available to authorized users. * Danilo E. Fernandes [email protected] 1



Division of Nephrology, Department of Medicine of the Federal University of São Paulo (UNIFESP), São Paulo, Brazil

2



Division of Rheumatology, Department of Medicine of the Federal University of São Paulo (UNIFESP), São Paulo, Brazil

3

Division of Immunology, Fleury Medicine and Health Laboratories, São Paulo, Brazil



Recently, great progress has been made in understanding the pathogenesis of membranous nephropathy (MN) with the discovery of circulating autoantibodies to M-type phospholipase A2 receptor (PLA2R) as well as glomerular antiPLA2R-containing immune complex deposits in most cases of primary MN in adu