Lymphocyte responsiveness to phytohemagglutinin and its modification by serum inhibitor in breast cancer patients.

Lymphocyte responsiveness in stimulation with phytohemagglutinin (PHA) and the inhibitory effect of autologous serum on lymphocyte responsiveness were investigated in 55 patients with breast cancer. Lymphocytes from patients, even in the late stage of the disease, as well as from normal healthy control, showed an ability to respond to the stimulation with PHA in the presence of pooled normal serum, while lymphocyte responsiveness in the presence of autologous serum was markedly reduced in stage III and IV patients. Similar result was found in the examination of lymphocyte responsiveness with relation to tumor size, where lymphocytes from patients with a large tumor of more than 5 cm in diameter were less responsive when cultured with autologous serum. From these results, it is reasonable to conclude that in patients with breast cancer, the apparent reduction of lymphocyte reactivity may be due to serum inhibitor that may adhere to the lymphocytes, rather than a primary lymphocyte impairment.