Background: Post-transplant immune reconstitution has a significantly effect on "hematopoietic stem cell transplantation (HSCT)" outcomes. Delay in immune reconstitution increases the risk of infections and disease relapse after transplantation. Recovery of T cells is mainly thymus-dependent. Thymic atrophy is associated with various clinical conditions that lead to a reduced thymic output. Therefore, thymus rejuvenation can improve immune reconstitution after transplantation. Zn plays a pivotal role in thymus rejuvenation. Zinc deficiency can lead to thymic atrophy, which increases susceptibility to infections. Zinc supplementation restores the immune system by boosting thymus output and T cell repertoire production. This protocol was designed to investigate the effect of oral zinc supplementation on T cell recovery in patients undergoing HSCT. Methods: Forty eligible candidates for autologous-HSCT will be selected. They will be randomly divided into "zinc" and placebo groups. Subsequently, they will receive three zinc or placebo tablets for the first 30 days post HSCT (+1 to +30), followed by one tablet or placebo for 60 days (+31 to +90). The copy numbers of "recent thymic emigrants (RTEs)" T cells and "T cell Receptor Excision Circles (TREC)" will be assessed before and after the intervention. All patients will be followed up for 365 days post HSCT for relapse and infection. Discussion: This clinical trial is the first to determine the efficiency of "zinc" in T cell recovery post HSCT. If successful, an available and inexpensive drug will improve immune system reconstruction after HSCT, reduce the risk of infection, particularly viral infections, and increase patient survival. Trial registration number: IRCT20191211045701N1

Objectives: This study investigated the possible prognostic factors for the long-term survival (Cure Rate) of Hodgkin Lymphoma patients who underwent HSCT. Methods: This retrospective cohort study analyzed 116 Patients diagnosed with Hodgkin Lymphoma who received autologous hematopoietic stem cell transplantation (Auto-HSCT) between the years 2007 and 2014 and followed up until 2017. The information regarding patients' survival had been collected using phone calls, and their pre-transplant information was available in the archived documents. Prognostic effects were investigated using long-term survival models. Results: Patients with obesity had five times higher odds of long-term survival (cure) than the others (P=0.06). Also, the recurrence experience after HSCT negatively impacted the curing potential by 78% (P=0.05). Also, with 32 years as the change point, patients younger than 32 had 76% fewer odds of surviving long-term (P=0.03), and Poor transfused stem cell dose of CD34+ (<0.16 × 10 6 cells/ml) reduced the odds of long-term survival by 92% (P=0.01). Conclusion: According to the statistical models used in this study, obesity can increase the curing potential of Hodgkin lymphoma after transplantation. Meanwhile, aging, poor transfused CD34+ cells, and recurrence after HSCT were associated with lower survival following HSCT.