Detection of circulating immune complexes associated with brain tumors

Sera from 30 patients with primary brain tumors were studied for the presence of circulating immune complexes by means of two different assays: the solid-phase conglutinin-binding test and the 125I-labeled Clq-binding test. Control sera were obtained from 16 healthy donors, and intra-assay control sera from 5 patients with intracerebral metastases from adenocarcinoma. The data yielded by both methods show the highest incidence of positivity in the metastases (80%), followed by poorly differentiated tumors (50%) and well-differentiated tumors (10%). The results obtained suggest that high levels of circulating immune complexes depend on the degree of histological differentiation of the tumor and on the length of the clinical history, since they were found not only in anaplastic tumors but also in tumors classified as benign but with a long clinical history.