In a tiny study of eight patients who got stem‑cell transplants, giving the peptide thymosin‑alpha‑1 for two weeks boosted several immune signaling proteins without causing graft‑versus‑host disease, but it didn’t change the numbers of major T‑cell types.

The present study was designed to investigate the effect of thymosin α1 (Tα1) administration in infective recipients of hematopoietic stem cell transplantation (HSCT) for hematologic malignancies. Eight patients were enrolled in our study, including seven allo-HSCT patients and one auto-HSCT patient. These patients were allocated randomly into the treatment group (four cases) and control group (four cases). Tα1 was used in the treatment group to test its effectiveness in infection control. The concentrations of cytokines IFN-γ, IL-2, IL-4, IL-10, and IL-12 were observed, and the levels of CD3(+), CD4(+), and CD8(+) T cells, as well as of CD4(+)/CD8(+) and CD4(+)/CD25(+) regulatory T cell (Treg) were measured. When Tα1 was administered for 2 weeks, the concentrations of these cytokines were increased after 1 month in the treatment group. Interestingly, the levels of IFN-γ, IL-2, IL-10, and IL-12 were increased in the treatment group more than those in the control group, whereas there were no significant differences between the treatment and control group in the levels of CD3(+), CD4(+), and CD8(+) T cells, or in CD4(+)/CD8(+) or CD4(+)/CD25(+) Treg cells. Notably, Tα1 administration did not cause acute or chronic graft versus host disease (GVHD). We conclude that Tα1 administration is safe and may impact favorably on immune function, and that it may improve resistance to infection and induce immunotolerance without GVHD.