After stomach cancer surgery, patients lose a lot of immune cells like T, B, and NK cells. Giving the peptide thymosin‑alpha‑1 helped keep these cells from dropping as much, especially T and B cells. This suggests the peptide can protect the immune system during big physical stress, though the study was in cancer patients, not healthy people.

Patients with locally advanced gastric cancer often face postoperative complications and insufficient short-term outcomes. Understanding the changes in peripheral lymphocyte subsets following laparoscopic D2 gastrectomy is critical to addressing these challenges and enhancing postoperative recovery. This study investigates the dynamics of peripheral lymphocyte subsets in gastric cancer patients post-laparoscopic D2 gastrectomy. Our goal is to identify factors contributing to postoperative reductions in these immune cells, thereby improving management strategies. We retrospectively analyzed clinicopathological data from 169 gastric cancer patients, focusing on perioperative lymphocyte subset variations. Utilizing univariate and multivariate analyses, we identified factors significantly influencing lymphocyte reductions after surgery. By postoperative day 7, we observed median decreases in T cells, B cells, NK cells, and memory T cells of -26.1%, -30.8%, -44.8%, and -2.3%, respectively. In contrast, naive T cells and regulatory T cells increased by 6.0% and 15.0%. Thymosin alpha 1 (T&#x3b1;1) treatment proved to be a protective factor, significantly reducing the decline in T and B cell counts (<i>p</i>&#x2009;=&#x2009;0.05). Multivariate analysis identified higher Interleukin-1&#x3b2; levels (HR&#x2009;=&#x2009;3.66, <i>p</i>&#x2009;=&#x2009;0.01), longer operation times (HR&#x2009;=&#x2009;2.98, <i>p</i>&#x2009;=&#x2009;0.02), and T&#x3b1;1 therapy (HR&#x2009;=&#x2009;0.15, <i>p</i>&#x2009;=&#x2009;0.01) as independent predictors of T cell reduction. These findings highlight T&#x3b1;1's potential as a therapeutic intervention to mitigate lymphocyte depletion, suggesting its incorporation into postoperative care could enhance immune recovery and patient outcomes. This study illuminates key immunological changes following gastric cancer surgery, offering pathways to improve postoperative management and patient health.