Review proposes a disease-driving subset of Gd-IgA1 in IgA nephropathy

IgA nephropathy is a common primary glomerular disease in which galactose-deficient IgA1 (Gd-IgA1) deposits in the glomeruli. In this review, Yoshihito Nihei and Yusuke Suzuki revisit the role of Gd-IgA1 in disease pathogenesis, drawing on longitudinal changes in serum Gd-IgA1 and proteinuria reported in recent therapeutic trials. The article does not report a new clinical study or participant sample size.

The authors propose that not all circulating Gd-IgA1 is equally pathogenic. They describe a potentially disease-relevant subset that may originate in mucosal tissues, have molecular properties favoring mesangial deposition, and form immune complexes capable of activating complement. This subset, termed “pathogenic Gd-IgA1,” is proposed as a contributor to glomerular inflammation and clinical manifestations such as hematuria and proteinuria.

The framework may help refine understanding of IgA nephropathy and guide research into therapies that selectively target disease-driving Gd-IgA1. These are proposed mechanistic features, not validated clinical criteria or a basis for changing treatment. The article is a conceptual review, and the supplied text does not provide evidence that testing for this subset can guide care.