T-zone histiocytes in adenocarcinoma of the lung in relation to postoperative prognosis

Infiltration of T-zone histiocytes (Langerhans' cells and their precursors) and macrophages was investigated by immunohistochemical methods with the use of anti-S100 protein and anti-lysozyme antibodies in 40 Stage Ia cases of adenocarcinoma of the lung. Varying population densities of S100+ T-zone histiocytes were demonstrated in 31 (77.5%) of 40 adenocarcinomas; however, lysozyme+ macrophages were found in almost equal quantities in all cases of adenocarcinoma. The distribution of T-zone histiocytes was clearly different from that of macrophages. Namely, the former was mainly interspersed among the tumor cells, whereas macrophages were found in the stroma and around necrotic foci. The prognosis of Stage Ia adenocarcinoma cases was related to the density of T-zone histiocytes in tumor tissues. Patients with marked infiltration of T-zone histiocytes survived longer than those without or with only slight infiltration (P less than 0.05). Such relationship was not observed with regard to macrophages. This indicates that T-zone histiocytes infiltrating within the tumor and regional lymph nodes may play a role in host defense mechanisms against tumor in the early stage of adenocarcinoma of the lung.