Chemotherapy-induced changes of perforin expression in cytotoxic T lymphocytes and natural killer cells of colon carcinoma patients

MD Mrakovčić-Šutić PhD^a, M Petković MD PhD^b, G Zamolo MD PhD^c, MD Belac-Lovasić^b, Č Milin Ing PhD^a, B Radošević-Stašić MD PhD^a, D Rukavina MD PhD^a

^aDepartment of Physiology and Immunology, ^cDepartment of Pathology; Medical School, University of Rijeka, Rijeka, Croatia, ^bDepartment of Radiotherapy and Oncology, Clinical Hospital Center, Rijeka, Croatia

Potent cytolytic machinery responsible for the protection against the neoplastic and altered-self cells is mainly related to the presence of cytoplasmatic granules containing molecule perforin and associated granzymes, which mediate target cell DNA degradation. AIM: To determine the effects of standard chemotherapy with 5-fluorouracil and leucovorin in colon carcinoma patients on expression of perforin in peripheral blood mononuclear cells (PBMNC) and their subsets. METHODS: The blood samples were taken from 15 colon cancer patients, classified as Dukes^'B or Dukes^'C, before the operation and during the chemotherapy. The control group comprised of normal age-mated laboratory donors. Simultaneous detection of cell surface membrane antigens and intracellular content of perforin was made by flow-cytometry. RESULTS: The data showed that the percentage of total perforin positive cells among the PBMNC in colon cancer patient during the chemotherapy was 30% higher than in the control group. Double staining of surface markers and perforin content revealed that augmented particularly CD8+ T lymphocytes (19,5 % versus 10% in control group; p<0,01). The calculation of the frequency of perforin expressing cells in the various lymphocytes phenotype also showed that after chemotherapy the percentage of perforin positive cells among the CD3+ cells arose to 55,70% (versus 18% in the healthy population) and among the CD4+ cells to 6,20% (versus 3,5%). The frequency of perforin positive cells among the populations of CD16+ and CD56+ cells was, however, found to be declined, from 68% to 51,49%, and from with 92% to 63,1%, respectively. CONCLUSIONS: The data emphasize the marked changes induced by chemotherapy in cytotoxic T lymphocytes and cells with NK phenotype, pointing to the important role of cytolytic molecule perforin in immune reaction on aberrant cells.

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in poster session 1091 (Vaccine trials).