The analysis of mononuclear cell infiltrations in colorectal adenocarcinoma

Mononuclear cell (MNC) populations in tissue specimens from 11 colorectal adenocarcinomas and 1 mucinous adenocarcinoma were analyzed, applying different monoclonal antibodies (MoAB). Tumor epithelium could be characterized by MoAB VEP9, predominantly binding to mucus secreted by the tumor cells. In approximately 30%-50%, the tumor epithelium also reacted in a patchy pattern with the MoABs OKT10 and OKIa, which define in the peripheral blood activated and HLA-DR expressing cells. T-lymphocytes, as defined by the MoAB 9.6, and T-lymphocyte subpopulations, as characterized by the MoABs OKT4 and OKT8, were found in the intratumoral stroma and in peritumoral inflammatory areas. Quantifying the relative amounts of mononuclear cell subpopulations in the different stroma compartments, a predominance of OKT10- and OKIa-defined and MoAB-S39-reactive cells was observed. NK cells, as labelled by the MoAB Leu-7, were only demonstrated singularly in different areas of the stroma. Nonlymphoid structures such as vessel walls were shown to express antigens recognized by the MoABs OKIa, OKT10, and Leu-7. In some instances, nerve structures were labelled by the MoABs OKIa, OKT10, S39, and Leu-7. Using semiquantitative analysis, no correlation could be obtained between the intratumoral and peritumoral infiltration with T-lymphocytes, T-lymphocyte subpopulations and monocytic cells, and histopathological tumor grading and staging.