Characterization of mononuclear cells in peripheral blood and primary tumour infiltrates of patients with stage D prostate cancer

The identification and distribution of the mononuclear cell subpopulation in the peripheral blood and primary tumour infiltrates of patients with metastatic Stage D prostate cancer have been evaluated and compared employing monoclonal antibodies to T-cell subsets. Limited to the study of four patients, these preliminary observations, nonetheless point to significant (p < 0.05) decreases in T-cells (OKT3) and helper (OKT4) cells and increases in monocytes and null cells, i.e. natural killer (NK) cells, as identified by OKM1 in tumour infiltrates compared to their distribution in peripheral blood. The implication here is that mononuclear cells, particularly NK cells, are not prevented from infiltrating the tumour in significant numbers in patients with advanced disease. The paradox of the presence of NK cells in the absence of cytolytic function is considered in view of the demonstrated local immunosuppressive properties of the prostate's secretory milieu, i.e., seminal plasma.