CD1A dendritic cells predominate in transitional cell carcinoma of bladderand kidney but are minimally activated

Purpose: In this study, we employed similar techniques to detail dendritic cell subsets within bladder transitional cell carcinoma and kidney transiti onal cell carcinoma. Materials and Methods: To identify both the CD1a(+) and CD1a(-) antigen-exp ressing dendritic cell populations we employed a double labeling technique to identify non-lineage-expressing leukocytes similar to that employed to i solate blood dendritic cells. Results: Dendritic cells were found in significant numbers within both blad der and kidney derived transitional cell carcinoma. Almost all the dendriti c cells among the tumor cells belonged to the CD1a(+) subset of epithelial dendritic cells. Similar numbers of dendritic cells were observed in the la mina propria adjacent to the tumor. These dendritic cells belonged predomin antly to the CD1a(-) subset. These differences appear to reflect the differ ent dendritic cell phenotypes reported for the epidermis and dermis. Conclusions: The number of dendritic cells increased as the grade of the tu mor increased, reflecting an overall higher leukocyte density in higher gra de tumors. However, a possible trend for less dendritic cell activation in higher grade cancers was noted, raising the intriguing possibility that thi s might be a relevant prognostic factor, to be confirmed in a larger study.