Increased expression of CD40 ligand on activated T cells of patients with colon cancer

Purpose: Proper function of T lymphocytes is crucial for an effective destruction of cancer cells in vivo. Identifying the cell surface molecules on the T cells that may be involved in this antitumor response may help to elucidate immunological factors influencing the biology of human tumors. Experimental Design: Differences in the antigen expression profile of unstimulated and stimulated peripheral blood T-lymphocytes from patients with colon cancer and from normal controls were determined using flow cytometry. Results: Freshly isolated peripheral blood T cells of patients with colon cancer did not differ in their phenotype significantly from those of patients with nonmalignant diseases. In contrast, in vitro stimulated T cells of patients with colon cancer had a significantly increased expression of CD40 ligand (CD40L, CD154) compared with activated T cells of the control group; increased CD40L expression was also found in the CD4(+)- and CD8(+)-T-cell subpopulations. Conclusions: The data presented support additional studies investigating the role of CD40L in the immune response against colon carcinoma.