CD1a dendritic cells predominate in transitional cell carcinoma of bladder and kidney but are minimally activated.

Abstract

In this study, we employed similar techniques to detail dendritic cell subsets within bladder transitional cell carcinoma and kidney transitional cell carcinoma. To identify both the CD1a+ and CD1a- antigen-expressing dendritic cell populations we employed a double labeling technique to identify non-lineage-expressing leukocytes similar to that employed to isolate blood dendritic cells. Dendritic cells were found in significant numbers within both bladder and kidney derived transitional cell carcinoma. Almost all the dendritic cells among the tumor cells belonged to the CD1a+ subset of epithelial dendritic cells. Similar numbers of dendritic cells were observed in the lamina propria adjacent to the tumor. These dendritic cells belonged predominantly to the CD1a- subset. These differences appear to reflect the different dendritic cell phenotypes reported for the epidermis and dermis. The number of dendritic cells increased as the grade of the tumor increased, reflecting an overall higher leukocyte density in higher grade tumors. However, a possible trend for less dendritic cell activation in higher grade cancers was noted, raising the intriguing possibility that this might be a relevant prognostic factor, to be confirmed in a larger study.