Beta-Glucan Supplementation Improves Clinical Outcomes and Preserves Immune Homeostasis in Patients with Advanced Solid Tumors Receiving Chemotherapy: A Prospective Phase II Randomized Three-Arm Clinical Trial

Chemotherapy-induced immune dysregulation remains a major challenge in patients with advanced solid tumors. β-Glucan has been reported to possess immunomodulatory properties; however, its longitudinal effects on immune homeostasis during chemotherapy remain unclear. In this prospective, randomized phase II study, patients receiving chemotherapy were assigned to receive β-glucan powder (with L-glutamine and bioactive protein from bovine colostrum), β-glucan capsules (with L-glutamine), or standard care. Clinical outcomes, serial hematologic parameters, longitudinal immune profiling, and an in vitro Jurkat T-cell viability assay were evaluated. Compared with controls, β-glucan supplementation improved the disease control rate, accelerated neutrophil recovery, and maintained a more stable neutrophil-to-lymphocyte ratio during chemotherapy. Longitudinal immune profiling demonstrated greater stability of T-cell, NK-cell, NKT-cell, and KIR (CD158)-expressing immune-cell populations in β-glucan supplementation groups, suggesting attenuation of chemotherapy-induced immune remodeling. Both β-glucan formulations showed comparable immunomodulatory effects, although the expression of CD158b(+) and CD158i(+) NK-cell subsets remained more stable in the powder group during later treatment. In vitro, β-glucan significantly reduced Jurkat T-cell viability, indicating direct biological activity in addition to its clinical immunomodulatory effects. These findings suggest that β-glucan supplementation helps preserve immune homeostasis during chemotherapy and may serve as a promising adjunctive immunonutritional strategy for patients with advanced solid tumors.