ANTI-PHOSPHOLIPASE A2 RECEPTOR ANTIBODIES - DIAGNOSTIC RELIABILITY FOR DIAGNOSING PRIMARY MEMBRANOUS NEPHROPATHY

Abstract

The etiology of membranous nephropathy (MN) remains incompletely understood. As a specific glomerular disease, it manifests itself in about 80% of cases as primary membranous nephropathy (PMN). According to Roncko et al., in other cases, the causes of the disease may be of a different nature, such as hepatitis infection, autoimmune disease, etc. (2021). In these cases, it is referred to as secondary (SMN). In a review of the scientific literature, data indicate that biopsy of kidney is used as the “gold standard” for making a diagnosis MN (Kalantari et al., 2017; Lai et al., 2015). The method is also invasive and, according to Dimitrios-Anestis et al. (2009), is often accompanied by complications of various kinds, including pain or bleedin. In rarer cases, according to Parish (1992), it may be accompanied by other infectious complications, as well as improperly punctured other tissue. The role of autoantibodies binding the phospholipse A2 receptor (PLA2R) in the clinical management of MH has been emphasized in recent years. Therefore, detection of these antibodies is thought to make them specific for the diagnosis of PMN (Li et al., 2022) and an important diagnostic tool (Netti et al., 2019) for monitoring the disease and assessing the response to treatment (Obrisca et al., 2015). Authors such as Hofstra et al. (2012) and Hoxha et al. (2014) point out the need to implement new clinical laboratory methods for quantitative determination of this indicator, which are easy to perform and reliable. Data from the scientific literature show that in clinical laboratory practice for determining antibodies against PLA2R there are qualitative, semi-quantitative or quantitative methods. The goal we set for our study is to determine the diagnostic reliability of the concentration of antiphospholipase A2 receptor antibodies (anti-PLA2R) in serum of patients with PMN and also their cut-off value. A total of 233 subjects were studied in this study - healthy subjects and patient groups. The patient group included 52 with PMN, 12 with SMN, 49 with other nephropathies (ON) and 120 clinically healthy subjects (HC). To determine a serum concentration of anti-PLA2R autoantibodies, an ELISA kit (Anti-PLA2R ELISA, IgG, EUROIMMUN, Lübeck, Germany) was used, and the results were read using an MR-96A microplate reader from MINDRAY. The obtained results were statistically processed, which allowed the calculation of criteria a diagnostic reliability about the anti-PLA2R antibodies indicator. We also determined the cut off value of a test using a receiver operating characteristic (ROC) curve constructed by us. Data analysis was statistically processed using the Med Cal cv.18.5 program, 2018 Med Cal c Software. ELISA method for а quantitative determination of anti-PLA2R antibodies has shown good diagnostic reliability. This allows it to be introduced into clinical laboratory practice and its routine use. We received the cut-off value 19.84 RU/ml. This value allows the diagnosis of PMN and can be used to distinguish these patients from other forms of MN. All these characteristics of the ELISA method determine its preference in its application in routine clinical laboratory practice.