Decreased production of immunoglobulin M and A in autoimmune pancreatitis.
BACKGROUND
Autoimmune pancreatitis (AIP) is a rare type of chronic pancreatitis caused by an autoimmune abnormality. It is well known that high serum concentrations of IgG4 are helpful for making a diagnosis of AIP; however, it is unclear whether there are abnormalities in the production of other immunoglobulins in AIP.


METHODS
We examined the immune condition of AIP patients before and after glucocorticoid treatment, focusing on serum levels of IgG, IgG4, IgM and IgA, and compared the results with those in other hepato-pancreatic diseases, such as autoimmune hepatitis, primary biliary cirrhosis, chronic pancreatitis and pancreatic carcinoma.


RESULTS
IgM and IgA were decreased in patients with untreated AIP. IgM and IgG or IgG4 were negatively correlated in patients with AIP. The ratios of IgG to IgM and IgG to IgA in patients with AIP were significantly increased compared with the other diseases. The diagnostic sensitivity of IgG to IgM and IgG to IgA was 0.800 and 0.950, and the specificity of each ratio was 0.703 and 0.728, respectively, in the differentiation of AIP from the other diseases. IgM was not significantly changed after glucocorticoid treatment in the patients with AIP, while IgG, IgG4 and IgA decreased.


CONCLUSIONS
The ratios of IgG to IgM and IgG to IgA may serve as novel diagnostic markers to differentiate AIP from other hepato-pancreatic diseases. Furthermore, low concentrations of IgM and IgA may be involved in the pathogenesis of AIP.
Taguchi
Masashi
M
Third Department of Internal Medicine, University of Occupational and Environmental Health, Japan School of Medicine, Yahatanishi-ku, Kitakyushu, Japan. tagu@med.uoeh-u.ac.jp
Kihara
Yasuyuki
Y
Nagashio
Yoshikuni
Y
Yamamoto
Mitsuyoshi
M
Otsuki
Makoto
M
Harada
Masaru
M
D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood* / Q000187:drug effects; D007074:Immunoglobulin G / Q000097:blood / Q000187:drug effects; D007075:Immunoglobulin M / Q000097:blood* / Q000187:drug effects; D008107:Liver Diseases / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010182:Pancreatic Diseases / Q000276:immunology; D050500:Pancreatitis, Chronic / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D012680:Sensitivity and Specificity
D005938:Glucocorticoids; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M