Effect of serum factors and cell washings on leukocyte adherence inhibition in breast cancer patients.

A total of 81 individuals, including 41 breast cancer patients, 20 patients with other types of malignant tumors, and 20 normal volunteers, were studied in order to evaluate whether leucocyte reactivity directed to soluble tumor-associated antigens could be increased by extensive cell washings and could be blocked by preincubation with autologous serum. When 41 leucocyte samples were pretreated with autologous serum, washed 3 or 6 times, mean percentage of leucocyte adherence inhibition difference between control extract and breast cancer extract were -2.4 +/- 2.0, 5.8 +/- 1.3, and 10.0 +/- 1.2, respectively. The results of cells preincubated with serum were significantly different from those of cells washed 3 times and 6 times (both P less than 0.001 by Student's t-test). The results of cells washed 3 times were significantly different from those of cells washed 6 times (P less than 0.05 by Student's t-test). Serum blocking factors correlated with tumor burden and clinical stage. However, leucocyte reactivity against breast cancer extract did not correlate with tumor burden or clinical stage in breast cancer patients.