Changes in T Lymphocyte Subsets in Different Tumors Before and After Radiotherapy: A Meta-analysis

Abstract

PurposeRadiation therapy (RT) induces an immune response, but the relationship of this response with tumor type is not fully understood. This meta-analysis further elucidated this relationship by analyzing the changes in T lymphocyte subsets in different tumors before and after radiotherapy.MethodsWe searched English-language electronic databases including PubMed, EMBASE, and the Cochrane Library to collect studies on the changes in peripheral blood CD3+ T lymphocytes, CD4+ T lymphocytes, and CD8+ T lymphocytes before and after radiotherapy in tumor patients from January 2015 to April 2021. The quality of the included literature was evaluated using the NOS scale provided by the Cochrane Collaboration, and statistical software RevMan 5.4 was used to analyze the included literature. P<0.05 was considered to indicate statistical significance.ResultsA total of 19 studies in 16 articles involving 877 tumor patients were included. All data were collected within 1 month before or after radiotherapy. Meta-analysis showed that numbers of CD3+ T lymphocytes (SMD: -0.40; 95% CI [-0.75, -0.04]; p = 0.03) and CD4+ T lymphocytes (SMD: -0.43; 95% CI: [-0.85, -0.02]; p = 0.04) were significantly reduced after radiotherapy compared with before treatment, but there was no statistically significant difference for CD8+ T lymphocytes (SMD: 0.33; 95% CI: [-0.88, 0.74]; p = 0.12). Subgroup analysis showed that peripheral blood T lymphocytes decreased in head and neck cancer. However, in prostate cancer and breast cancer, there was no significant change in peripheral blood. 1 month after radiotherapy, it has a potential proliferation and activation effect on lymphocytes in esophageal cancer and lung cancer. The results showed that CD8+T lymphocytes increased in peripheral blood after SBRT. Radiotherapy alone reduced CD3+ T lymphocyte numbers.ConclusionsWithin 1 month of radiotherapy, patients have obvious immunological changes, which can cause apoptosis and reduction of T lymphocytes, and affect the balance of peripheral blood immune cells. The degree of immune response induced by radiotherapy differed between tumor types.

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“…Immunosuppression is prevalent in cancer patients, manifested by the abnormal function and disproportion of lymphocyte subsets, resulting in cancer cells successfully escaping immune surveillance of the host [16]. Step-bystep radiotherapy and chemotherapy have killing effects on T lymphocytes and normal tissue cells when killing cancer cells [17]. 125I seed implantation under the guidance of TPS system can advance accurate and precise radiation range; in addition to ensure the effective radiation dose in cancer target area, the damage to surrounding organs and tissues is small, which is beneficial to improve immune function of the body [9].…”

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“…In this context, a recent meta-analysis by Wang et al. summarized the effects of RT in different types of tumor, concluding that during the first month of RT, the values of T lymphocytes undergo an evident reduction due to apoptosis ( 40 ).…”

A Water-Soluble Polysaccharide from the Fibrous Root of Anemarrhena asphodeloides Bge. and Its Immune Enhancement Effect in Vivo and in Vitro

“…T lymphocytes play an important role in immune response and immune recognition. CD3 + and CD4 + are helper T cells and the two main T lymphocyte subsets according to their surface markers [ 31 ]. Besides, flow cytometry is an established technology used for the determination of different types of cells [ 32 ].…”