Distribution of glomerular IgG subclass deposits in malignancy-associated membranous nephropathy

Background. Several studies have shown a predominant glomerular deposition of IgG4 in patients with idiopathic membranous nephropathy (MN), whereas significant depositions of other IgG subclasses have been shown in patients with lupus-associated MN and bucillamine-induced MN. Methods. We examined the distribution patterns of glomerular IgG subclass deposits in 10 patients with malignancy-associated MN (M-MN) and in 15 patients with idiopathic MN by immunofluorescence (IF) microscopy. Results. The glomerular IF intensities of IgG1 and IgG2 were significantly stronger in the malignancy group than in the idiopathic group (P<0.05). In contrast, there were no differences in glomerular IF intensities of IgG3 and IgG4 between the two groups. Conclusion. Our findings suggest that the distribution patterns of glomerular IgG subclass deposits are different in idiopathic MN and M-MN. The strong IF intensity of glomerular IgG1 and IgG2 in M-MN may provide a possible predictor for this condition.