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

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.Peripheral blood samples were collected preoperatively from 28 patients with digestive cancers before and after intravenous administration of LNT (2 mg x 3 times/week). The proportions of CD4+ T-cells producing intracellular cytokines were determined with flow cytometry.After LNT treatment, CD4+ IFN-gamma+ T-cell percentages increased significantly (p < 0.05), whereas CD4+ IL-4+ T-cell and CD4+ IL-6+ T-cell percentages decreased significantly (p < 0.02). No significant change occurred in proportions of CD4+ IL-10+ T-cells. The after/before LNT treatment percentages ratio of CD4+ 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+ IL-4+ T-cells correlated positively with that of CD4+ IL-6+ T-cells (p < 0.05).LNT apparently can cancel Th2-dominant condition in patients with digestive cancers and may improve the balance between Th1 and Th2.