Circulating immune complexes detected by binding of radiolabelled protein A in patients with oral cancer and oral premalignant lesions.

Circulating immune complexes were determined in 48 patients with oral squamous cell cancer, 17 patients with oral keratosis and 49 controls, using a rapid sensitive assay using a Staphylococcus aureus immunoadsorbent. Concentrations of immune complexes were significantly higher in patients with oral cancer and in patients with oral keratosis than in controls, but the levels in those with oral cancer were not significantly different from those in keratosis. Immune complexes might be responsible for the cell-mediated immune defect in patients with cancer in the head and neck.