Detection of antigen-specific immune complexes in sera of gastric and esophageal cancer patients.

Using the murine monoclonal antibodies against human gastric cancer cell antigens designated MG7 and MGd1, we developed a sandwich ELISA to detect the levels of antigen-specific immune complexes (IC) in human sera. By this assay, only 6.7%(6/90) of healthy blood donors and 9.2%(6/65) of patients with chronic gastritis had antigen-specific IC in sera exceeding the cut-off value. Whereas 21.4%(6/28) of patients with colorectal cancer, 18.2%(4/22) of patients with hepatocellular cancer, 11.4%(4/35) of patients with lung cancer and 9.5%(2/21) of patients with breast cancer had elevated levels of the antigen-specific IC. In contrast, 58.7%(54/92) of patients with gastric cancer and 53.3%(24/45) of patients with esophageal cancer were positive for this antigen-specific IC. Determination of levels of antigen-specific IC in sera may be useful in serologic diagnosis of patients with gastric and esophageal cancer.