[Demonstration of circulating CEA or CEA-like antigens and immunoglobulin G containing immune complexes in colorectal carcinoma].

A sandwich method was developed for the detection of carcinoembryonic antigen (CEA) and CEA-like molecules and immunoglobulin G (IgG) containing immune complexes (CEA-IgG-IC) in human sera. Rabbit anti-CEA ( Dako , FRG) was adsorbed to polypropylene tubes. CEA-like molecules and IgG containing immune complexes bound to the solid phase. They were detected by binding peroxidase-labelled anti-IgG antibodies and quantified by measuring the optical density (OD) at 492 nm after oxidation of orthophenylene diamine. Sera of 68 controls had a mean OD 492 of 1.19 +/- 0.26 (means +/- SD). An extinction of more than 1.97 (means + 3 SD) was judged as elevated. Fourteen of 69 patients after surgical treatment of colorectal carcinoma showed elevated OD 492 up to a value of 3.92. In five patients with benign diseases of colon or rectum normal values were found. In 7 of 41 patients without recurrence or metastases CEA-IgG-IC were elevated although the CEA was normal, and in one case both parameters were elevated. In four of 22 patients with tumor progression CEA-IgG-IC and CEA were elevated, whereas in two cases only CEA-IgG-IC were found.