PHENOTYPIC CHARACTERIZATION OF THE DENDRITIC CELL INFILTRATE IN PROSTATE-CANCER

Purpose: To investigate whether dendritic cells (DC), which as profess ional antigen presenting cells have the capacity to stimulate immune r esponses against tumour associated antigens, are recruited into and ac tivated within prostate cancer. Materials and Methods: Immunoenzyme an d immunofluorescence labelling was used to identify leucocyte and DC s ubsets within 15 cases of prostate cancer. Cell numbers were compared with numbers in adjacent normal prostatic tissue. Total DC numbers wer e identified as CD45(+) leucocytes not coexpressing any lineage specif ic markers. The Langerhans cell (LC) subset was detected using anti CD la staining and activated DC were identified by their expression of e ither CD83, CD86 or CMRF44. Results: DC were found to represent a smal l subset of leucocytes present in both benign and malignant prostatic tissue. Statistically there were significantly less DC and LC in prost ate cancer compared with normal prostatic tissue, While only a small s ubset of DC expressed markers of activation in prostate cancer, this w as significantly more than the virtual absence of activated DC in norm al prostatic tissue. Conclusions: This is the first time that DC have been studied in prostate cancer using the relatively new DC specific m onoclonal antibodies CD83 and CMRF-44. These findings suggest that the re is no active recruitment of DC into prostate cancer and those DC pr esent are only minimally activated.