Immunoglobulin a nephropathy: Pathological markers of renal survival in paediatric patients.

IgA nephropathy (IgAN) is one of the leading causes of glomerulonephritis characterized by the findings of IgA and IgG immune deposits in the mesangium of kidney biopsies from patients with persistent microscopic haematuria. IgAN is frequently detected among adolescents and young adults. IgAN presents a highly variable course that includes a spectrum from a very mild disease to end-stage renal disease (ESRD). There are several clinical and histological factors that strongly determined the final outcome of patients with IgAN. Pathological variables associated with unfavorable outcomes are mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity and interstitial fibrosis/tubular atrophy, according to the Oxford classification. Moreover, some studies also suggest a role for complement activation in the pathogenesis of IgAN. In this regard, staining for C4d may be an independent risk factor for the development of ESRD in IgAN. Despite the growing number of studies assessing IgAN risk factors, this kind of investigation in paediatric patients is still very limited. The aim of this article is to revise pathological markers related to deterioration of renal function in paediatric patients with IgAN, particularly those that can independently affect renal survival.