A comparison of the diagnostic efficacy in type 1 autoimmune pancreatitis based on biopsy specimens from various organs.
BACKGROUND
Comprehensive immunostaining evaluation of the biopsy specimens from various organs with type 1 autoimmune pancreatitis (AIP) has not been elucidated. Our aim was to clarify which of these biopsy specimens and counting method could be a useful tool for supporting the diagnosis of AIP.


METHODS
We retrospectively evaluated biopsy specimens from pancreas (n = 19), stomach (n = 28), duodenum (n = 27), duodenal papilla (n = 25), colon (n = 19), liver (n = 11), bile duct (n = 24), and minor salivary gland (n = 13) in 36 patients with AIP. Positive IgG4 immunostaining (>10 plasma cells/high-power field [HPF]) and positive IgG4/IgG ratio (>40%) of biopsy specimens from 8 sites of 6 organs in one HPF and an average from 3 HPFs were compared between AIP and controls.


RESULTS
The sensitivity of IgG4 immunostaining for AIP in one HPF were 16% in pancreas, 14% in stomach, 15% in duodenum, 52% in duodenal papilla, 11% in colon, 27% in liver, 21% in bile duct and 8% in minor salivary gland, respectively. The positive IgG4 immunostaining of the duodenal papilla in one HPF showed the highest sensitivity (52%) and accuracy (73%) among the 8 sites. It also showed the highest sensitivity among 4 different counting methods (IgG4 immunostaining in one HPF and 3 HPFs, both IgG4 immunostaining and IgG/IgG4 ratio in one HPF and 3 HPFs), but there were no significant differences with respect to specificity and accuracy.


CONCLUSIONS
IgG4 immunostaining of swollen duodenal papilla with more than 10 IgG4-positive plasma cells in at least one HPF is useful for supporting the diagnosis of AIP.
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Hiroaki
H
Yamashita
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. Electronic address: inaito@med.nagoya-cu.ac.jp.
Itaru
I
Naitoh
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Takahiro
T
Nakazawa
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Kazuki
K
Hayashi
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Katsuyuki
K
Miyabe
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Shuya
S
Shimizu
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Hiromu
H
Kondo
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Michihiro
M
Yoshida
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Shuichiro
S
Umemura
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Yasuki
Y
Hori
Department of Community-based Medical Education, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Hirotaka
H
Ohara
Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Satoru
S
Takahashi
Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Takashi
T
Joh
D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000276:immunology / Q000473:pathology*; D015415:Biomarkers / Q000378:metabolism; D001706:Biopsy; D004064:Digestive System / Q000276:immunology / Q000473:pathology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000276:immunology / Q000473:pathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D015415:Biomarkers; D007074:Immunoglobulin G
Biopsy specimen; IgG immunostaining; IgG4 immunostaining; IgG4/IgG ratio; Type 1 autoimmune pancreatits