Research advances of idiopathic membranous nephropathy with non-nephrotic range proteinuria

Membranous nephropathy，an autoimmune kidney disease，is one of the major causes of nephrotic syndrome. However，not all patients with membranous nephropathy present with nephrotic syndrome and some of them develop non-nephrotic range proteinuria（24-hour urine protein quantification <3.5 g/d）at the time of diagnosis. Overall prognosis is decent. The 2020 KDIGO guidelines stated that patients with membranous nephropathy whose 24-h urinary protein level <3.5 g/d without a risk of progression required no therapy of immunosuppressants. However，some studies reported that most patients with non-nephrotic proteinuria progressed rapidly into nephrotic syndrome in the subsequent course of disease. Prognosis was poor. Therefore it is imperative to identify high-risk groups early and intervene timely. This review summarized the latest research advances of membranous nephropathy with nonnephrotic proteinuria in both domestic and foreign literatures to provide references for clinical practices.