Immunohistochemistry of human chronic pancreatitis tissue specimens. Consecutive sections of chronic pancreatitis tissues were subjected to immunohistochemistry using antibodies against alphaSMA (A; SMA), vimentin (B; VIM), CD31 (C), CD45 (D), collagen1 (E; COL) and fibronectin (F; FBN). Arrows: area around packed clusters of mononuclear cells. Arrowheads in A-C: pancreatic stellate cells (SMA- and VIM-positive, CD31-negative). Arrowhead in D: loosely distributed area of mononuclear cell infiltration. Arrowhead in E&F: areas of less intense immunoreactivities for collagen1 and fibronectin. Dotted arrows: Areas of strong collagen1 and fibronectin staining. Original magnification: ×50. (G) Arrows: areas of loosely distributed/single mononuclear cells, dotted arrows: area without mononuclear cells. (H&I) Arrows/dotted arrows: corresponding areas to (G).