Focal segmental glomerular sclerosis: do not overlook the role of immune response

Focal and segmental glomerular sclerosis (FSGS) is a histological pattern characterized by the partial sclerosis of some, but not all, glomeruli. It may be secondary to diverse etiologies such as mutations of podocyte key genes, loss of nephrons, drugs, and virus infection. However, in most cases of FSGS, the etiology is unknown and these forms are called idiopathic (primary) FSGS. A number of different pathogenic hypotheses have been proposed. The frequent recurrence of nephrotic proteinuria after renal transplantation has attracted the attention to search for plasma factors eventually implicated in the pathogenesis. However a decisive and unifying hypothesis is still lacking. On the other hand, recent findings indicate the involvement of cellular immunity and possibly autoantibodies in the pathogenesis of some forms of FSGS. In this paper we report on the recent advances in the pathophysiology of idiopathic FSGS and suggest the possibility that at least some forms of idiopathic FSGS may be caused by autoimmune reactivity.