Heterogeneity of histiocytes in primary lung cancer stained with anti-S100 protein, lysozyme and OKT 6 antibodies.

The heterogeneity of histiocytes in primary lung cancer was investigated by immunohistochemical methods using anti-S100 protein and anti-lysozyme antibodies on paraffin sections and OKT-6 monoclonal antibody on frozen sections. T-zone histiocytes (Langerhans cells and their precursors stained by anti-S100 protein and/or OKT-6 monoclonal antibodies) heavily infiltrated tumor tissues and regional lymph nodes in cases of moderately or well-differentiated adenocarcinoma, especially in areas of papillary growth or bronchiolo-alveolar pattern. These cells were interspersed amongst tumor cells showing dendritic figures and were occasionally present in squamous cell carcinoma. However, they were seldom found in other histological types, particularly in small cell carcinoma and carcinoid tumor. The distribution of these cells was different from that of lysozyme-positive macrophages. In this connection, T-zone histiocytes were thought to have a different immunological function from that of the monocyte-macrophage series against lung cancer. The closely similar reactivity of T-zone histiocytes with anti-S100 protein and OKT-6 monoclonal antibodies indicated that these two markers can be employed for paraffin and frozen sections, respectively.