Carcinoembryonic antigen and cystic fibrosis protein in blood from cystic fibrosis homozygotes and heterozygote carriers.

Carcinoembryonic antigen (CEA) activity was measured by radioimmunoassay in blood from cystic 
fibrosis (CF) homozygotes, heterozygote carriers of CF, normal healthy controls, and 
other patient controls with carcinomas involving gastrointestinal organs. All samples were 
also screened by electrofocusing for cystic fibrosis protein (CFP), a metabolic 
marker previously shown to be associated with the CF gene. Significantly 
increased levels of CEA activity were found in all CFP-positive groups; 
however, with one exception all patient controls with marked increases in 
CEA activity were CFP- negative. Immunodiffusion of perchloric acid extracts of 
CEA-like material from heterozygote carrier blood indicated that the CEA-like material, 
which was elevated in homozygotes and heterozygotes for CF, showed only 
partial identity with two separate CEA preparations obtained from colon carcinomas 
and was not identical to either A, B, or O(H) blood 
group substances. This glycoprotein material did, however, react with three different 
anti-CEA antisera. Our finding of an abnormally increased glycoprotein in cystic 
fibrosis, taken together with previous reports demonstrating abnormalities in the carbohydrate 
portion of glycoproteins found in various exocrine secretions in CF, further 
suggests that the primary defect in this disease is manifested partly 
as a defect in glycoprotein metabolism. This defect may result from 
an abnormality in one or more of the glycosyltransferases, possibly caused 
by a more primary defect in polyamine metabolism. 