Trends in pediatric nephrotic syndrome

Abstract

Nephrotic syndrome (NS) is relatively common in children, with most of its histological types being minimal changed disease. Its etiology has long been attributed to lymphocyte (especially T-cell) dysfunction, while T-cell-mediated vascular hyperpermeability increases protein permeability in glomerular capillaries, leading to proteinuria and hypoproteinemia. Based on this etiology, steroids and immunosuppressive drugs that are effective against this disease have also been considered to correct T-cell dysfunction. However, in recent years, this has been questioned. The primary cause of NS has been considered damage to glomerular epithelial cells and podocyte-related proteins. Therefore, we first describe the changes in expression of molecules involved in NS etiology, and then describe the mechanism by which abnormal expression of these molecules induces proteinuria. Finally, we consider the mechanism by which infection causes the recurrence of NS.

Keywords: Nephrotic syndrome; Gene; Immunity; Viral infection; Children

Core Tip: There is no doubt that some vascular hyperpermeability factor is involved in the incidence of proteinuria in idiopathic nephrotic syndrome (INS). However, no etiological molecule has been identified in INS as a factor for increasing the permeability of renal glomerular capillaries with reproducibility and clinical consistency. In addition, since the onset is sometimes observed in the family, there is high incidence of INS in East Asian children and there is the association of steroid-sensitive NS in childhood in Japan with the HLA-DR/DQ region, it is highly possible that some genetic factors are involved in the onset of NS. In our opinion, INS is a multifactorial disease in which immunological stimuli, trigger the production of substances that impair podocytes, resulting in dysfunction of the slit membrane and cause proteinuria.