Immunoregulatory effects of the antitumor polysaccharide lentinan on Th1/Th2 balance in patients with digestive cancers

Background: Recent studies demonstrated that patients with advanced cancer may have impaired cell-mediated immunity caused by an imbalance between Th1 and Th2 responses. We evaluated the ability of lentinan (LNT) to modulate Th1 and Th2 responses in patients with digestive cancers. Methods: Peripher al blood samples were collected preoperatively from 28 patients with digest ive cancers before and after intravenous administration of LNT (2 mg x 3 ti mes/week). The proportions of CD4(+) T-cells producing intracellular cytoki nes were determined with flow cytometry. Results: After LNT treatment, CD4( +) IFN-gamma (+) T-cell percentages increased significantly (p<0.05), where as CD4(+) IL-4(+) T-cell and CD4(+) IL-6(+) T-cell percentages decreased si gnificantly (p<0.02). No significant change occurred in proportions of CD4( +) IL-10(+) T-cells. The after/before LNT treatment percentages ratio of CD 4(+) IFN-gamma (+) T-cells correlated negatively with that of CD4(+) IL-4() T-cells (p<0.01). The after/before treatment percentage ratio of CD4(+) I L-4(+) T-cells correlated positively with that of CD4(+) IL-6(+) T-cells (p <0.05). Conclusion: LNT apparently can cancel Th2-dominant condition in pat ients with digestive cancers and may improve the balance between Th1 and Th 2.