Analysis of IgG subclass staining for IgG immunofluorescence-positive IgA nephropathy.

IgG1-positive IF staining intensity was highest among each IgG subclass in IgG IF-positive IgAN biopsies. A negative correlation was revealed between the age at biopsy and IgG1 IF intensity. Oxford E and C scores were higher in patients with IgG IF-positive IgAN than in those with IgG IF-negative IgAN. The Oxford score was not significantly different between the IgG subclasses, but the IF intensity of IgG had a positive correlation with the IF intensity of IgG1 in IgG IF-positive IgAN biopsies. Further studies should assess relationships between IgG subclass IF deposition and examine the pathogenesis of IgAN.