Langerhans cell and HLA class II molecules distribution in lung carcinoma

We have evaluated Langerhans cell (LC) distribution in 19 lung carcinomas and 1 carcinoid tumor, furthermore investigating HLA class II molecules expression by the neoplastic cells; this was done using, in immunohistochemical tests, a polyclonal antiserum anti S-100 protein for the identification of LCs and a mouse Monoclonal Antibody (MoAb) for the detection of HLA class II -DR molecules. Our results indicate that LCs are poorly represented in lung carcinomas and likewise HLA class II molecules are scarcely expressed by the neoplastic cells; this might be important in understanding the ominous prognosis of lung carcinomas since both parameters investigated play a central role in the immune response against human neoplasia, LCs as antigen presenting cells and HLA class II molecule as restriction elements during antigen stimulation of CD4+ T lymphocytes.