الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The obstructive cholangiopathy can be classified in either benign and malignant causes. The benign causes could be divided into either congenital causes or acquired. They can affect any portion of the biliary tree either the intrahepatic, extrahepatic portions or both.
Human B cells are known to produce 4 subclasses of IgG (IgG1, IgG2, IgG3, IgG4) with each subclass having different biological function.
In healthy adult serum, IgG1, IgG2, IgG3 and IgG4 represent 65%, 25%, 6% and 4% of total IgG pool, respectively, but these portions may be altered in certain diseases.
Associations of IgG4 antibodies are reported in range of chronic inflammatory and autoimmune conditions that feature infiltration of target organs by IgG4-experessing cells.
Cholelithiasis is the most common benign cause of biliary tract obstruction. Approximately 15% of the patients with cholelithiasis present with choledocholithiasis.
Cholangiocarcinoma is one of the malignant causes of obstructive cholongiopathy. The incidence of cholangiocarcinoma has been increasing The predisposing factors include congenital anomalies (e.g choledochal cyst and caroli’s syndrome) as well various conditions associated with chronic inflammation (primary sclerosing cholangitis, ulcerative colitis and parasitic infection).
Also obstructive cholangiopathy is frequently observed in immunoglobulin G4 associated cholangitis (IgG4-sc) which usually resolves by steroid therapy. The diffuse cholangiographic abnormalities observed in (IgG4-sc) may resemble those in primary sclerosing cholangitis and the presence of segmental stenosis suggest cholangiocarcinoma.
The aim of this work is to investigate the diagnostic value of bile immunoglobulin G4 in patients with obstructive cholangiopathy.
The present study was carried out on 40 patients with obstructive cholangiopahty: 25 patients diagnosed with choledocholithiasis and 15 patients diagnosed with cholangiocarcinoma.
The diagnosis of choledocholithiasis and cholangiocarcinoma was established upon the co-evaluation of findings originating from clinical presentation, laboratory analysis, imaging studies and endoscopic retrograde cholangiopancreatography.
The result of the current study showed that there was a significant high level of bile immunoglobulin G4 in cholangiocarcinoma group compared to choledocholithiasis group.
The mean bile IgG4 level for cholangiocarcinoma patients was 1.45 0.95 ng/mL, and the mean level for choledocholithiasis patients 0.78 0.62 ng/mL. the median value of bile IgG4 in cholangiocarcinoma patients was 1.15 ng/mL and the median value of bile IgG4 in choledocholithiasis patients was 0.54 ng/mL. and the mean level of serum IgG4 for cholangiocarcinoma patients was 2.66 1.75 ng/mL and the mean level of choledocholithiasis patients was 2.47 1.31 ng/mL. And the median value of serum IgG4 of cholangiocarcinoma patients was 1.75 ng/mL and for choledocholithiasis patients was 2.5 ng/mL.