MACROPHAGE AND DENDRITIC CELL INFILTRATION IN HEAD AND NECK SQUAMOUS-CELL CARCINOMA - AN IMMUNOHISTOCHEMICAL STUDY

A study was undertaken to help us reach a better understanding of the tumor-infiltrating pattern of lymphoid cells and in particular of mono cyte-derived cells, namely the CD68+, acid-phosphatase-expressing scav enger macrophages and the MHC-class-II- and S100-antigen-presenting de ndritic cells in head and neck squamous-cell carcinoma. In the stroma of the tumors distinctive small fields of lymphocytes were found, the T cell areas of these fields being intermingled with dendritic cells. Intra-epithelial dendritic cell infiltration was low. The infiltrative pattern of macrophages was similar to patterns described in earlier s tudies with substantial stromal invasion and inconsistent intra-epithe lial invasion, but small granuloma-like structures of CD68+ macrophage -like cells, found in the stroma of tumors, have not been reported bef ore. The histochemical localization of the tumor-infiltrated dendritic cells and macrophages supports the view that the former cells are inv olved in the sensitization to tumor antigens, whereas the latter cells are involved in tumor cytotoxicity/scavenging of tumor cell debris. A lthough it has been shown in the past that transmembranal (TM) factors (p15E-like factors) present in the serum and tumor of patients with c ancer of the head and neck have suppressive effects on monocyte/macrop hage/dendritic cell function, a relationship between the intensity of epithelial staining for TM factors and the infiltrative pattern of mon ocytes/macrophages/dendritic cells could not be demonstrated.