Identification of acute-phase proteins (APP) in circulating immune complexes (CIC) in esophageal cancer patients' sera

The occurrence of increased circulating immune complexes (CIC) in sera of patients with esophageal cancer and their usefulness for diagnosis and prognosis have not been demonstrated. Circulating acute-phase proteins (APP) related to esophageal cancer have been described but without any association with CIC. This is a study to measure CIC, C-reactive protein (CRP), and alpha(1)-acidic glycoprotein (AAG) in pretreatment esophageal cancer sera and to analyze the presence of both APP associated with these CIC. Increased CIC levels were found ill 57% of sera from esophageal cancer patients; elevated CRP was detected in 87% and AAG in 57%. Western blot analysis showed the presence of CRP and AAG in CIC-derived fractions. We conclude that: (1) CIC, CRP, and AAG are elevated in esophageal cancer sera; (2) they may be considered possible useful clinical parameters in pretreatment esophageal cancer patients; (3) these APPs appear in CIC precipitates and may possibly be involved in their composition.