RESUMO
A radioimmunoassay (RIA) was developed and used to determine the level of fragment E [a fibrinogen/fibrin degradation product (FDP)] and of fragment-E-containing substances (FES) in sera and effusion fluids of patients with malignant diseases. Sera of patients with other diseases and sera of healthy individuals served as controls. Results were expressed as units/ml (U/ml), one unit being equivalent to 40 ng pure fragment E. Effusion fluids of both malignant and nonmalignant origin contained relatively high levels of fragment-E-containing substances, up to 7,500 U/ml. Normal sera had less than 30 U/ml, while sera of patients with a variety of neoplastic or nonneoplastic conditions contained larger amounts, reaching to hundreds and, in rare cases (some patients with rheumatoid arthritis), even thousands of U/ml. Some of the highest levels in the malignant sera were found in samples from patients with Burkitt's lymphoma and stomach cancer. About 10%-20% of the reactive material in effusions and 20%-40% in the sera consisted of fragment E. These results confirm earlier findings of high FDP levels in neoplasia. Given the higher accuracy of the radioimmunoassay and its suitability for large scale testing, it would appear worthwhile to continue such studies to explore the clinical usefulness of the RIA for fragment E.