Figure 5.

Detection of galactose-deficient IgA1 (Gd-IgA1). Serum Gd-IgA1 levels measured by Helix aspersa agglutinin (HAA)-based ELISA, due to HAA specificity for terminal GalNAc, is significantly higher in patients with IgAN than in healthy subjects (a) [32,33]. The left figure of (a) was published in Kidney International 2007, 71, 1148-54, Moldoveanu, Z. et al., Copyright 2007 Elsevier Inc and is republished with permission. The right figure of (a) is republished with permission of Oxford University Press, from Nephrology Dialysis Transplantation 2008, 23, 1931-9, Shimozato, S. et al., Copyright 2008 Oxford University Press. Detection of Gd-IgA1 using monoclonal antibody against human Gd-IgA1 hinge region (HR) peptide (b) [154]. The figure (b) was published in Journal of Nephrology 2015, 28, 181-6, Hiki, Y. et al., Copyright 2014, The Author(s). This article is under the terms of the Creative Commons CC BY license. A variety of IgA1 HR O-glycoforms can be detected by high-resolution mass spectrometry according to the difference in mass arising from the number of attached monosaccharides to the amino acid backbone of the IgA1 HR (His²⁰⁸-Arg²⁴⁵). The number of N-acetylgalactosamine (GalNAc; □) and galactose (Gal; ●) are shown above the individual peaks (c).