Infection-related immunoglobulin A nephropathy or IgA-dominant postinfectious glomerulonephritis; what is in a name?

Abstract

Immunoglobulin A nephropathy (IgAN) is the most common glomerulonephritis worldwide. However, its incidence and prevalence vary depending on racial and geographical factors. IgAN is a highly heterogeneous disease with wide clinical and pathological variability. The defining and consistent feature of IgAN is the dominance or co-dominance of IgA deposits in the glomeruli on immunofluorescence (IF) microscopy. However, recent reports suggest that a number of post-infectious glomerulonephritis (PIGN) cases also exhibit dominance or co-dominance of IgA deposits on IF microscopy. Therefore, a debate has arisen on labeling these cases either as infection-related IgAN (a form of secondary IgAN) or IgA-dominant PIGN. Although the majority favors the later nosology, this issue has remained unresolved, as is the issue of labelling this condition as PIGN when, in fact, the infection is often intercurrent, and no latent period is found in this condition. This brief narrative review aims to discuss the salient features of this condition and issues related to its nomenclature.