[Immunoregulatory effects of PSK on the Th1/Th2 balance and regulatory T-cells in patients with colorectal cancer].

It is very important for immunotherapy to release Th2-dominated and Treg-dominated immunological conditions in patients with malignant diseases. In the present study, we assessed the population of CD4+IL-10+T-cells and CD4+Foxp3+T-cells in peripheral blood in patients with colorectal cancer using a flow cytometric analysis, and we investigated whether Th2-dominated and Treg-dominated condition could be modulated by PSK. Peripheral blood samples were collected preoperatively from 40 patients with colorectal cancer before and after oral administration of PSK (3 g/day × 1 week). After PSK treatment, CD4+IL-10+T-cell percentages decreased in 63% of patients and CD4+Foxp3+T-cells percentages decreased in 63% of patients. However, no correlation was found between the ratio of CD4+IL-10+T-cell percentages and that of CD4+Foxp3+T-cell percentages after/before PSK treatment. These results suggest that PSK could release Th2-dominated and Treg-dominated immunological condition in patients with colorectal cancer. Further examinations are needed to investigate the after/before percentage ratio of CD4+Foxp3+T-cells can be useful predicting parameters for the selection of responders of PSK.