The Relationship between T Regulatory Cells (Tregs) and Cognitive Impairment in Elderly Patients

Background: Alzheimer’s disease-related dementia and mild cognitive impairment are characterized by cognitive decline and neuroinflammation. Regulatory T cells play a crucial role in modulating inflammatory responses. Previous studies have suggested Treg dysfunction in neurodegenerative diseases, yet their role in dementia remains poorly understood. Objective: This study investigates the relationship between Tregs, their cytokine markers (TGF-β and IL-10), and cognitive impairment in elderly patients. Methodology: This study included 60 participants categorized into three groups: mild cognitive impairment (MCI), dementia, and healthy controls. Flow cytometry was used to assess Treg percentages, while enzyme-linked immunosorbent assay (ELISA) quantified TGF-β and IL-10 levels. Cognitive function was assessed using the Addenbrooke’s Cognitive Examination-III and other relevant scales. Results: No significant difference in Treg percentages or absolute counts was observed between study groups. However, both TGF-β and IL-10 levels were significantly higher in MCI) and dementia groups compared to controls (p < 0.001), with MCI patients showing higher levels than those with severe dementia. Notably, TGF-β and IL-10 levels negatively correlated with cognitive scores, suggesting a link between elevated cytokine levels and cognitive decline. Absolute T cell and CD4+ T cell counts were significantly lower in the dementia group compared to MCI. Conclusion: While Treg numbers did not vary significantly across cognitive stages, elevated TGF-β and IL-10 levels point to an immunosuppressive environment associated with cognitive decline. These findings suggest that immune modulation, particularly through Tregs and cytokines, may play a role in the progression of dementia, highlighting potential therapeutic avenues for future research.