Enumeration of lymphocytes and their subpopulations identified by bacterial adherence in blood smears of patients with breast tumors.

Peripheral blood lymphocyte counts were determined in 57 breast clinic patients. These patients were grouped into four clinical/pathological groups: 18 had benign breast disease, 13 had a history of breast cancer but were free of disease at the time of the study, 7 had a history of breast cancer and were free of disease at the time of the study but were on adjuvant chemotherapy, and 19 had active metastatic breast cancer. Two parameters were investigated in a double blind study: 1) the absolute lymphocyte counts and 2) the percentages of lymphocytes that bound different bacteria as markers of lymphocyte subpopulations in conventionally stained blood smears. A significant reduction in mean lymphocyte counts was demonstrated in patients with advanced disease. A significant increase in these counts was found in patients who were free of disease following surgical treatment alone. The T1T2 cells (our denomination), the subpopulation of cells responsible for specific killing in vitro and for suppression of natural cytotoxic cells, was significantly reduced in patients with advanced disease under treatment. The T/B cell ratio in all groups was the same and within normal range. These observations suggest that the observed decrease in the total lymphocytes is due not only to an overall decrease in all classes of lymphocytes but especially in those responsible for specific cell-mediated reactions. They also show that bacteria can be used as reliable reagents for the identification of lymphocyte subpopulations in blood smears.