Zinc as a therapeutic adjunct: enhancing t-cell reconstitution in hematopoietic stem cell transplant recipients—a double-blind clinical study

Effective immune reconstitution (IR) following hematopoietic stem cell transplantation (HSCT) is vital for increasing long-term patient survival and reducing the risk of posttransplant infections. A key indicator of successful immune recovery is the generation of recent thymic-enriched T cells (RTEs), which directly reflects thymic activity. Zinc (Zn), an essential trace element, has been shown to play a pivotal role in supporting immune function and thymic output. This study assessed how Zn supplementation influences RTE levels and overall immune recovery in patients undergoing HSCT. In this double-blind, randomized, placebo-controlled clinical trial, 38 patients who underwent autologous HSCT were randomly assigned to receive either Zn supplementation (n = 19) or placebo (n = 19). The intervention group was administered three 30 mg Zn gluconate tablets daily during the first 30 days post-transplant, followed by one tablet daily from day 31 to day 90. T-cell subsets, including RTEs, were measured via flow cytometry at baseline, day 30, and day 90. Absolute lymphocyte counts (ALCs) were also monitored. Nutritional intake and serum Zn and copper levels were assessed to control for dietary confounders. On day 90 posttransplant, patients receiving Zn supplementation presented a significantly greater ALC than did those in the placebo group (p = 0.009). Furthermore, the Zn group presented a substantial increase in the percentage of RTEs at both day 30 (p = 0.008) and day 90 (p = 0.025), whereas the placebo group did not demonstrate changes. These findings suggest that Zn supplementation positively influences thymic output and contributes to early T-cell reconstitution. Zn supplementation facilitates immune recovery following autologous HSCT by increasing ALC and RTE generation. These results highlight the potential utility of Zn as an adjunctive therapy to promote thymic regeneration and immune competence in transplant recipients. IRCT20191211045701N1/Date: 2020–06-12. This registration confirms adherence to ethical standards and facilitates verification of study details from 2020–06–12. 1. Zn supplementation significantly enhances T-cell recovery after HSCT. 2. RTEs increased notably in the Zn group. 3. Higher absolute lymphocyte counts were observed at 90 days post-transplant with Zn. 4. This study suggests that Zn is an effective adjunct therapy for immune reconstitution. 5. These findings support the role of Zn in improving long-term survival rates post-HSCT