Effect of Inhibited T lymphocyte Function on Depressive Symptoms in Breast Cancer Patients with Depression

Background: Depression has a high incidence among patients with breast cancer, but the relationship between depression and cancer-related physiological changes is not clear. Objectives: To explore the effect of T lymphocytes on breast cancer depression and the patient’s quality of life. Methods: : This is a cross-sectional study. A total of 93 breast cancer patients with depression were recruited, 46 of whom underwent T lymphocyte, cortisol, BDNF, TNF-α, and IL-1β collection. We analysed the correlation between the indicators in these 46 participants and constructed two intermediary structural equations between their T lymphocytes and depression, as well as their T lymphocytes and their quality of life. Results: : The results showed that CD4 + had a positive correlation with BDNF (r=0.334, P=0.023) and that BDNF had a negative correlation with HAMD-24 (r=-0.390, P=0.007). Both CD3 + and CD8 + cells were negatively correlated with cortisol (r=-0.358, P=0.015, r=-0.411, P=0.005), and cortisol was positively correlated with FACT-B (r=0.435, P=0.003). The equations including CD4 + , BDNF, and HAMD-24, as well as the equations including CD3 + , CD8 + , cortisol, and FACT-B, were established. BDNF was the mediating variable between CD4 + and HAMD-24. Cortisol was the mediating variable between CD3 + , CD8 + and FACT-B. Neither HAMD-24 nor FACT-B could form a direct path with T lymphocytes. Conclusion: : T lymphocytes may be involved in the depression of breast cancer patients since a poor quality of life could inhibit T lymphocytes, and this may be the underlying physiological cause of breast cancer-related depression.