[1874] Expression of Other M2-Macrophage Markers in CD163+ Dendritic Macrophages in Lymphoplasmacytic Sclerosing Pancreatitis

Kaori Uchino, Kenji Notohara, Masayoshi Fujisawa, Yoji Wani, Akihiro Matsukawa. Himeji Red Cross Hospital, Himeji, Japan; Kurashiki Central Hospital, Kurashiki, Japan; Okayama University, Okayama, Japan

Background: CD163+ dendritic macrophages are one major component of lymphoplasmacytic sclerosing pancreatitis (LPSP). Although CD163 is considered to be a marker of M2-macrophages, further studies with other immunohistochemical markers are necessary to confirm the nature of these cells. In addition, these markers are potentially useful for the histological diagnosis of LPSP.
Design: Resected specimens of LPSP (13 patients), idiopathic duct-centric pancreatitis (IDCP, 2), acute pancreatitis (AP, 6), chronic pancreatitis (CP, 4) and pancreatic ductal adenocarcinoma (PDA, 17) were gathered. Serial sections from a representative block of each case were immunostained for M2-macrophage (CD163, CD204, CD205) and other monocyte/macrophage (CD11c, CD14, CD16) markers.
Results: In LPSP, dendritic macrophages seen in the lobules, pancreatic ducts and peripancreatic adipose tissue were consistently positive for CD163, CD204 and CD205. CD204 immunoreactivity of these cells was almost identical to CD163; and numerous cells were positive with both stains. CD205 immunoreactivity was weaker; and the number of positive cells was smaller. CD11c+ macrophages were fewer, but tended to be present more in the lobules rather than in the peripancreatic adipose tissue, notably when there was abundant lymphoplasmacytic infiltrate. Although the intensity was weaker, CD16 showed a similar staining pattern to CD163 and CD204. CD14+ cells were very few. In IDCP, AP, CP and PDA, small aggregates of CD163+, CD204+ and CD16+ macrophages were observed; but the immunoreactive cells were fewer than in LPSP, and were plump in shape rather than dendritic. Notably, proliferation of dendritic macrophages in the lobules was limited; although it was one of the striking features in LPSP. Few were positive for CD11c and CD14. A LPSP-like reaction seen in one case with PDA showed numerous CD163+ and CD204+ dendritic macrophages, even in the lobules.
Conclusions: CD163+ dendritic macrophages were also positive for CD204 and CD205, suggesting that they represent M2-macrophages. In addition to CD163, CD204 is also a useful marker to identify these dendritic macrophages. Although none of these markers are specific to LPSP, a larger number, diffuse distribution and dendritic shape of positive cells in LPSP are in contrast to other conditions except for rare PDAs with LPSP-like reaction. Identification of more CD11c+ macrophages in the lobules than in the peripancreatic adipose tissue may indicate that these macrophages are, in fact, heterogeneous in LPSP.
Category: Pancreas

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 258, Tuesday Morning


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