IGHA1 and anti-neutrophil cytoplasmic antibody-associated vasculitis: Fig 1A shows that s-Gd-IgA1 levels were significantly elevated in patients with IgAN compared with other kidney diseases (IgAN vs. LN, AAV, and MCD: 16.2 ± 9.1 vs. 12.7 ± 9.4, p = 0.008; 13.1 ± 7.3, p = 0.059; and 8.2 ± 4.8 μg/mL, p<0.001, respectively).