Analysis of sera from patients with breast cancer for blocking and induction of leukocyte adherence inhibition.

The correlation of serum capacity for blocking and arming with effector cell reactivity has been examined in patients with breast cancer by using the leukocyte adherence inhibition (LAI) assay. It was found that sera from breast cancer patients possessed the ability to make nonimmune mononuclear cells specifically reactive (i.e., armed) to the breast cancer extract and to specifically block the reactivity of mononuclear cells from breast cancer patients with the cancer extract. Sera from patients with breast cancer whose mononuclear cells were nonreactive to the corresponding tumor extract (6/8) showed higher blocking than sera from patients whose cells showed reactivity to the corresponding tumor extract (3/13). Similarly, sera from patients with positive LAI response (6/13) induced arming of normal mononuclear cells more often than sera from patients with negative LAI (2/8). There also appeared to be an inverse correlation between the capacities of serum from breast cancer patients to exhibit blocking and arming. That is, serum arming activity was found only in sera which showed no blocking, and serum blocking activity was detected only in sera without arming, activity, except for one sample. The possibility is discussed that immune complexes play a key role in both serum activities, and that their biphasic character might be dependent on the ratio of antigen of antibody.