#6905 PREVALENCE OF ANTIPLA2R ANTIBODIES IN EGYPTIAN PATIENTS WITH NEPHROTIC SYNDROME

Abstract Background and Aims Primary membranous nephropathy (PMN), a common form of the nephrotic syndrome, is an antibody-mediated autoimmune glomerular disease. Autoimmunity is driven by circulating autoantibodies that bind to one or more antigens on the surface of glomerular podocytes. PLA2R antigen is the most common and prevalent one among these antigens. Anti-PLA2R antibodies are measured in serum and detected within biopsies of primary membranous nephropathy patients. Up to the moment, no clear data about the prevalence of AntiPLA2R antibodies associated PMN in Egyptian patients. The aim of this work was to study the prevalence of antiPLA2R antibodies in Egyptian patients with nephrotic syndrome underwent renal biopsy. Method In this cross-sectional study we recruited 70 adult patients presented with nephrotic range proteinuria to Ain-shams university hospital and a private nephrology center in Cairo during a period of 20 months (from March 2020 to October 2021). All patients first presentation for whom laboratory investigations including serum anti-PLA2R antibodies titer by indirect immunofluorescence and kidney biopsy were done. Anti-PLA2R antibodies were measured in serum, checked in biopsies and correlated with biopsy findings. Results Membranous nephropathy (primary and secondary) was found by biopsy finding in 25 of 70 patients (35.7%) presenting with nephrotic range proteinuria. 21 patients (84%) of the cases of membranous nephropathy had been diagnosed with primary membranous nephropathy and 4 (16%) had been diagnosed with secondary membranous nephropathy. Circulating anti-PLA2R antibodies were detected within serum in 9 (42.85%) of primary MN cases while detection of anti-PLA2R antibodies within the glomerular extracts of primary MN cases was much higher; 17 patients (80.95%). There was positive correlation between serum AntiPLA2R Antibodies titer and U PCR (r = 0.839, P = 0.005) (Fig. 1). Conclusion A we may conclude that, most patients with primary membranous nephropathy have anti-PLA2R antibodies. Detection of anti-PLA2R antibodies within the biopsy has higher sensitivity than serum (80.95% versus 42.85%). Specificity of PLA2R to primary membranous nephropathy is 100%. Patients with high anti-PLA2R titer had higher baseline proteinuria than patients with lower anti-PLA2R titer.