Evaluation of Cellular Immunologic Responsiveness in the Clinical Management of Patients with Prostatic Cancer

Abstract

Host cellular responsiveness to tumour was evaluated in 37 patients with varying degrees of clinically active and inactive adenocarcinoma of the prostate by direct inhibition of leucocyte migration (ILM) employing saline extracts of pooled allogeneic normal, benign and malignant prostatic tissue as a source of antigen. The majority of these patients had received or were receiving conventional therapy at the time of evaluation. 13 (35%) prostatic cancer patients possessed clinically significant specific reactivity to malignant prostatic tissue, whereas only 1 (8%), of 13 control patients (11 healthy adults and 2 patients with carcinoma other than of the prostate: bladder and penis) possessed comparable reactivity. While the wide range of specific reactivity observed overall, including ‘stimulation’ of migration, compared with the mean percent ILM was very large, the SD of the mean specific percent ILM in the 13 prostatic cancer patients possessing clinically significant specific reactivity to malignant prostatic tissue, was most respectable. Since all reactions were allogeneic, these results indicated that prostatic cancer patients possessed cell-mediated immunity to presumably common prostatic tumour-associated antigens. Further evaluation disclosed that the incidence of patients possessing clinically significant reactivity to malignant tissue was almost identical regardless of the patient’s stage of malignancy, histological grade of tumour, or clinical status. The degree of sensitization of clinically significant reactivity to malignant tissue was, however, greater in patients with localized disease, low grade tumour, and clinically inactive disease, than in patients with advanced disease, high grade tumour, and clinically active disease. Evaluation of the possible correlation of specific reactivity to malignant prostatic tissue as a prognostic index of subsequent clinical responsiveness revealed a positive correlation with the degree of sensitization in 3 (43%) of 7 patients available for routine follow-up. Correlation in four patients was questionable due to the observations of ‘stimulation’ of migration rather than inhibition. While providing initial preliminary evidence of the presence of cell-mediated anti-tumour immunity in patients with prostatic cancer and promise of a possible prognostic index, the wide range in the variability of cellular responsiveness and the failure to identify clinically significant reactivity to malignant prostatic tissue in the majority (65%) of the patients evaluated, raises concern as to whether ILM employing saline extracts will provide the necessary in vitro assay of cellular responsiveness for the evaluation of prostatic cancer patients.