APRIL is concentrated on tumor cells by proteoglycans. (A) DLBCL lesions were stained with anti–syndecan-4 (green, 10 μg/mL) and Aprily-2 (red), (B) with anti–syndecan-4 (green) and anti-CD20 (red), and (C) with anti-CD20 (green) and Aprily-2 (red). Single stainings and the corresponding merge picture are representative of 4 patients.