In our recent report, serum Gd-IgA1 (s-Gd-IgA1) levels, quantified by a novel lectin-independent enzyme-linked immunosorbent assay (ELISA) using an anti-Gd-IgA1 monoclonal antibody (KM55) [27], were significantly elevated in patients with HSPN or IgAN compared to other kidney diseases [26]. Here, IGHA1 is linked to kidney disorder.