Prevalence of Anti-PLA2R Antibodies in Biopsy Proven Membranous Nephropathy in Egyptian Patients

Abstract

Abstract Background Membranous nephropathy (MN) is among the most common causes of the nephrotic syndrome in nondiabetic adults, accounting for approximately 20 to 30 percent of cases of nephrotic syndrome in White adults. MN is most often primary (previously called idiopathic), although it may be secondary with hepatitis B infection, autoimmune diseases as systemic lupus erythematosus (SLE), malignancies, and the use of certain drugs such as nonsteroidal antiinflammatory drugs (NSAIDs). MN in young females should raise the suspicion of SLE. Aim of the Work The aim of this work was to study the prevalence of anti-PLA2R antibodies in Egyptian patients with biopsy proven membranous nephropathy. Patients and Methods Our cross-sectional study included 70 Egyptian patients with nephrotic range proteinuria on first presentation for whom laboratory investigations including serum anti- PLA2R antibodies titer by indirect immunoflouresence and kidney biopsy were done. Results Membranous nephropathy has been diagnosed in 35.71% of adult Egyptian patients presented with nephrotic range proteinuria. 84% of the cases of membranous nephropathy had been diagnosed with primary membranous nephropathy and 16% diagnosed with secondary membranous nephropathy. Sensitivity of circulating anti-PLA2R antibodies in primary MN was 42.85% versus 80.95% for its detection within the glomerular extracts. Specificity of PLA2R is close to 100%; however, in other studies; PLA2R has been detected in the immune deposits of some patients with secondary MN. Patients with high anti-PLA2R titer had higher baseline proteinuria than patients with lower anti-PLA2R titer. Conclusion Membranous nephropathy (primary and secondary) may be considered the most common glomerulonephritis by biopsy finding in patients presenting with nephrotic range proteinuria followed by focal segmental glomerulosclerosis (35.7 %& 30% respectively). 84% of the cases of membranous nephropathy had been diagnosed with primary membranous nephropathy and 16% had been diagnosed with secondary membranous nephropathy. Circulating anti-PLA2R antibodies were detected within serum in 42.85% of primary MN cases while detection of anti- PLA2R antibodies within the glomerular extracts of primary MN cases was much higher (80.95%). Specificity of PLA2R is close to 100%; however, in other studies; PLA2R has been detected in the immune deposits of some patients with secondary MN. Patients with high anti-PLA2R titer had higher baseline proteinuria than patients with lower anti-PLA2R titer.