Fig. 2.

Immunohistochemistry of YKL-40 in ANCA-associated glomerulonephritis. Immunohistochemistry was performed on kidney tissues obtained from patients with non-proliferative glomerular disease (thin basement membrane, n = 3; disease controls) and from ANCA-associated glomerulonephritis (n = 5). a Positive tissue control stain in lymph node (× 400). b Negative disease control staining in non-proliferative GN (thin basement membrane lesion (× 200)). c, d YKL-40 staining in ANCA-associated glomerulonephritis, showing upregulation within tubular cells, and expression within crescentic lesions (c × 200; d × 400 same glomerulus). e Tubulointerstitial infiltrate in active AAV (× 200). ANCA, Anti-neutrophil cytoplasmic antibody; GN, Glomerulonephritis; AAV, ANCA-associated vasculitis