IF staining of the urinary sediments from patients with various kidney diseases revealed that the number of claudin1-positive cells was significantly larger in AAV than in IgA nephropathy (IgAN), Henoch–Schönlein purpura nephritis (HSPN), and healthy volunteers (p < 0.05, Dunnett’s test) (Figure 2), but the number of CD68-positive cells did not differ significantly between AAV and other glomerular diseases or healthy volunteers. The gene discussed is CLDN7; the disease is IgA glomerulonephritis.