Dendritic cells in selected head and neck tumors

Specimens from 17 head and neck tumor patients were immunohistochemically s tained with monoclonal antibodies against HLA-DR, CD1a, RFD1, LAG, CD3, CD4 , CD8, CD45RO, CD68, and cytokeratin to identify the nature and distributio n of dendritic cells (DCs), T cells, and macrophages. Small numbers of DCs were present in all but 2 specimens. They were located between the tumor ce lls and in the stroma, especially in areas of inflammatory cell infiltratio n. Variable numbers of T lymphocytes (cytotoxic and memory type) occurred i n the same locations. Numerous macrophages were found in the epithelium, in the stroma, and in the vicinity of tumor cells. The presence of DCs in hea d and neck tumors indicates that the organism has activated the immune surv eillance system and is trying to present tumor antigens. Considering the sp arsity of DCs, in the malignant tissues, the T cell response can be only li mited.