Circulating immune complexes in sera of patients with Burkett's lymphoma and nasopharyngeal carcinoma.

Sera of individuals with Burkitt's lymphoma and nasopharyngeal carcinoma, tested by consumption of hemolytic complement, were found by comparison with healthy individuals to have significantly increased levels of circulating immune complexes. The identity of the immune complexes was established by sucrose density gradient ultracentrifugation, which showed them to sediment between 10 and 19S. As they were adsorbable by rheumatoid factor--Sepharose 4B conjugates, it appeared that these complexes were composed of IgG. The complexes were retained by Concanavalin A--Sepharose columns and eluted by alpha methyl-D-mannoside, suggesting by analogy with model complexes that the antigens might be glycoproteins.