Prognostic significance of accessory cells and lymphocytes in nasopharyngeal carcinoma

Forty-five consecutive biopsy specimens of nasopharyngeal carcinoma (NPC) and 10 biopsies of healthy nasopharyngeal mucosa obtained from non-cancer patients were investigated by immunohistochemical methods. Monoclonal (B2, T1) and policlonal antibodies (against S-100 protein and lysozyme) with reference to infiltrating lymphocytes and accessory cells (monocytic/macrophagic and dendritic cells) were used. Variable population densities of dendritic cells (S100+) were demonstrated in 22 out of the 45 cases (49%) of NPC; the distribution of these cells was typically within the cancer nests. Monocytic/macrophagic cells (Lys+) were found along the tumor margins and interspersed among the tumor cells in 14 out of 45 (31%) cases. No significant statistical correlation between density of accessory cells and histological type of NPC (classified according to Micheau criteria) was found. Cases with a moderate to marked density of dendritic and monocytic/macrophagic cells survived longer than those with a slight one (mean survival of 63%, 67% and 29%, 27% respectively). In NPC tissues T-lymphocyte infiltration was prevalent. In contrast, B cells were numerous and T cells rare in normal control tissues. The intensity of T-cell infiltration was significantly high in cases with a marked density of S-100+ cells, according to the ability of these cells to present antigens to sensitized T-cells. This study suggests a prognostic significance for reactive cells infiltrating NPC, which means longer survival for cases associated with marked infiltration density of accessory cells.