Published in:
01-09-2010 | Original Article
Autoimmune pancreatitis-related diabetes: quantitative analysis of endocrine islet cells and inflammatory infiltrate
Authors:
Alton B. Farris III, Gregory Y. Lauwers, Vikram Deshpande
Published in:
Virchows Archiv
|
Issue 3/2010
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Abstract
In autoimmune pancreatitis (AIP), mechanism(s) of paradoxical glycemic control improvement (GCI) often occurring after pancreatic resection and steroid therapy are not fully elucidated. Using image quantitation, AIP cases (n = 10) with pre- and post-surgical glucose values were compared with chronic pancreatitis (CP) and normal pancreas (NP) regarding percent chromogranin immunohistochemistry (IHC) positivity as a surrogate marker of endocrine endowment; intra-islet T and B lymphocyte and plasma cell enumeration with CD3, CD20, and IgG4 IHC; and CD34 IHC islet vascularity quantitation. Postsurgical GCI, noted in 8/10 (80%) AIP cases, approached statistical significance (P = 0.07) compared to CP. Endocrine endowment reduction, noted by a lower percent of chromogranin + pancreatic parenchyma, was seen in AIP (4.54%) and CP (3.20%) compared to NP (7.95%); only the CP decrease was statistically significant (P = 0.02) since AIP often had ductular endocrine neogenesis. Regression suggested an inverse correlation between endocrine endowment and GCI in AIP (R = 0.62, P = 0.06). AIP islets were smaller and disrupted by inflammatory cell infiltration. Compared to CP, AIP islets had higher CD3 + and CD20 + cell densities. IgG4 + plasma cells were often present at a high density in AIP but typically preserved the islets. Intra-islet CD34 staining showed a lower average vascularity in AIP compared to NP (P = 0.05). This study reaffirms postsurgical GCI in AIP. Prominent intra-islet inflammation and decreased vascularity in AIP may contribute to diabetogenic effects. Endocrine cell neogenesis and relative islet preservation despite islet inflammatory infiltration may explain the paradoxical GCI in AIP.