Measurement of circulating biliary glycoprotein (CD66a) in liver diseases.
OBJECTIVE
Biliary glycoprotein (BGP), a member of the carcinoembryonic antigen (CEA) gene family, is produced by hepatocytes, and is suggested to function as a cell adhesion molecule, mouse hepatitis virus receptor, and tumor suppressor. Our aim was to establish an enzyme immunoassay for circulating BGP and to study its significance in liver diseases.


METHODS
For enzyme immunoassay, a monoclonal antibody (mAb), TS135, which recognizes BGP was used as a catcher, and biotin-labeled polyclonal anti-CEA antibodies were used as a tracer. Seventy-six serum specimens obtained from patients with various liver diseases were submitted to the assay.


RESULTS
The incidence of positivity for antigen TS135 in the serum samples of the 76 patients was 57.9%. The most significant correlation among conventional liver function tests was found between antigen TS135 and gamma-glutamyl transpeptidase (gamma-GTP). However, among the 56 patients whose serum antigen TS135 and gamma-GTP levels could be measured simultaneously, 5 were antigen TS135-positive and gamma-GTP-negative (8.9%) and 6 were antigen TS135-negative and gamma-GTP-positive (10.7%). The increased serum level of antigen TS135 in 6 cholangiocellular carcinoma (CCC) patients led us to the immunohistochemical study of CCC, in which 8 of the 8 tissue specimens tested were positive for mAb TS135, indicating the production of the antigen from CCCs.


CONCLUSIONS
This preliminary study suggests that the circulating antigen TS135 level correlates with gamma-GTP in liver diseases, but that TS135 may also have a unique significance, different from that of gamma-GTP, as a liver function test.
Kondo
Y
Y
First Department of Internal Medicine, Sapporo Medical University, Japan.
Hinoda
Y
Y
Akashi
H
H
Sakamoto
H
H
Itoh
F
F
Hirata
K
K
Kuroki
M
M
Imai
K
K
D000328:Adult; D000368:Aged; D000818:Animals; D000911:Antibodies, Monoclonal / Q000097:blood; D015703:Antigens, CD / Q000097:blood*; D000943:Antigens, Differentiation / Q000097:blood*; D001650:Bile Duct Neoplasms / Q000276:immunology; D001653:Bile Ducts, Intrahepatic / Q000276:immunology; D002272:Carcinoembryonic Antigen / Q000276:immunology; D015815:Cell Adhesion Molecules; D018281:Cholangiocarcinoma / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques; D008107:Liver Diseases / Q000276:immunology*; D051379:Mice; D008875:Middle Aged; D005723:gamma-Glutamyltransferase / Q000097:blood
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; C069847:CD66 antigens; D002272:Carcinoembryonic Antigen; C486183:Ceacam1 protein, mouse; D015815:Cell Adhesion Molecules; D005723:gamma-Glutamyltransferase