The effect of systemic corticosteroids on the innate and adaptive immune system in children with steroid responsive nephrotic syndrome

Clinical observations suggest that lipoid nephrosis is produced by a systemic abnormality of T-cell function resulting in the secretion of a circulating chemical mediator toxic to an immunologically innocent glomerular basement membrane. The lack of evidence of a humoral antibody response, remission induced by measles which modifies cell-mediated immunity, the therapeutic benefits of steroids and cyclophosphamide which also abate cell-mediated responses, and the occurrence of this syndrome in Hodgkin's disease support this hypothesis. The susceptibility of untreated patients to pneumococcal infections may be of primary or secondary pathogenetic importance. Taken together, the data suggest that this syndrome is a clinical expression of a self-limited primary immune-deficiency disease.

Glucocorticoids are small lipophilic compounds that mediate their many biological effects by binding an intracellular receptor (GR) that, in turn, translocates to the nucleus and directly or indirectly regulates gene transcription. Perhaps the most recognized biologic effect of glucocorticoids on peripheral T cells is immunosuppression, which is due to inhibition of expression of a wide variety of activationinduced gene products. Glucocorticoids have also been implicated in Th lineage development (favoring the generation of Th2 cells) and, by virtue of their downregulation of fasL expression, the inhibition of activation-induced T cell apoptosis. Glucocorticoids are also potent inducers of apoptosis, and even glucocorticoid concentrations achieved during a stress response can cause the death of CD4(+)CD8(+ )thymocytes. Perhaps surprisingly, thymic epithelial cells produce glucocorticoids, and based upon in vitro and in vivo studies of T cell development it has been proposed that these locally produced glucocorticoids participate in antigen-specific thymocyte development by inhibiting activation-induced gene transcription and thus increasing the TCR signaling thresholds required to promote positive and negative selection. It is anticipated that studies in animals with tissue-specific GR-deficiency will further elucide how glucocorticoids affect T cell development and function.

The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline on glomerulonephritis (GN) is intended to assist the practitioner caring for patients with GN. Two chapters of this guideline focus specifically on nephrotic syndrome in children. Guideline development followed a thorough evidence review, and management recommendations and suggestions were based on the best available evidence. Critical appraisal of the quality of evidence and strength of recommendations followed the Grades of Recommendation Assessment, Development and Evaluation (GRADE) approach. Chapters 3 and 4 of the guideline focus on the management of nephrotic syndrome in children aged 1-18 years. Guideline recommendations for children who have steroid-sensitive nephrotic syndrome (SNSS), defined by their response to corticosteroid therapy with complete remission, are addressed here. Recommendations for those with steroid-resistant nephrotic syndrome (SRNS) (i.e., do not achieve complete remission) are discussed in the companion article. Limitations of the evidence, including the paucity of large-scale randomized controlled trials, are discussed. This article provides a short description of the KDIGO process, the guideline recommendations for treatment of SSNS in children and a brief review of relevant treatment trials related to each recommendation.