Humoral antitumor immune responses in patients with breast cancer measured with the leukocyte adherence inhibition technique.

A modification of the hemacytometer leukocyte adherence inhibition (LAI) test was described. In this modification, 0.25% serum from patients with breast cancer was added with the relevant antigen to the assay system with the use of trypsinized leukocytes from control persons as indicator cells. The modified assay measured a humoral immune response. In studies of patients with untreated breast cancer (stages I and II) with the use of a KCl extract from a breast carcinoma or from MCF-7 cells as antigens, the modified LAI test was found to be at least as sensitive as was the ordinary test. In a blind study on sera collected from patients with breast cancer 0.5-2 years before the LAI measurements and stored at -20 degrees C, 15 of 18 (83%) patients had a positive response. Whereas the ordinary LAI test is limited to the use of fresh blood, the present test can be performed with small amounts of serum that can be frozen and stored.