Immunohistological analysis of tumour infiltrating lymphocytes in seminoma using monoclonal antibodies.

Immunological characterization of tumour infiltrating lymphocytes (TIL) by immunohistological techniques was carried out in 20 cases of stage I seminoma. Routine pathological examination of these surgical specimens showed typical seminoma in 20 cases. Eighteen cases showed obvious TIL and immunohistological staining on frozen specimens was performed in 12. TIL in seminomas were predominantly T-cells but B-cells were also identified. T-cells were distributed diffusely with predominance of the CD8+ phenotype judged semiquantitatively. In contrast to the distribution of T-cells, B-cells tended to accumulate and occasionally formed lymphoid follicles. In such follicles the phenotypic pattern of B-cell antigens was comparable with secondary lymphoid follicles in lymphoid organs. There is an immunologically complex response to seminoma by the host with a predominant infiltration of cytotoxic/suppressor T-cells and functional maturation of B-cells.