Regulatory T Cell and Nephrotic Syndrome

Abstract

The pathogenesis of idiopathic nephrotic syndrome (INS) has not been clearly understood. Most of the pediatric nephrologists currently considered that immune mediated factor derived from T cell is related in some way to INS. Some clinical findings supporting this hypothesis were shown as follows: the response of the disease to corticosteroids and to alkylating agents, the remission which is occurring in association with measles, and occurance of minimal change nephrotic syndrome (MCNS) in patients with Hodgkin’s disease. Reguratory T cell (Treg) is one of T cell component, which function to maintain the balance between self-tolerance and autoimmunity. It is known that Treg is responsible for the pathogenesis of many autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and myasthenia gravis. Recent reports also suggested the relationship between Treg and INS. We experienced two cases of INS which were thought to be due to reduction of Treg or impaired Treg function. First case was immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome complicated by MCNS. IPEX syndrome is caused by mutations in the FOXP3 gene that result in the defective development of Treg. After bone marrow transplantation, INS in this patients were achieved complete remission. This case imply that reduction of Treg may be cruicial for development of MCNS. Second case was polyglandular autoimmune syndrome (PGA) complicated by INS. The etiology of PGA is currently unknown, however, one of the most leading hypothesis is dysfunction of Treg. This case also imply that impaired Treg may be cruicial for development of INS. Together with previous reports, it is of much interest to consider Treg as one of the pathogenesis of INS. Further studies are needed to define a precise relationship between INS and Treg.