Background: Recently, it has been shown that immune responses are involved in the pathophysiology of cardiovascular diseases. In particular, a role of immunosenescent T cells has been described in cardiovascular diseases, such as atherosclerosis. In the present study, we evaluated the relationship between immunosenescent T cells and clinical parameters of vascular aging.
Methods: We examined the fraction of CD57⁺ and CD28^null T cells in 200 consecutive patients (age 58.6 짹 13.1 yrs, male 63%) who visited Severance Cardiovascular Genome Center between January and August 2011. Multicolor flow cytometer was performed to analyze surface phenotype of T cells. In addition, we measured pulse wave velocity (PWV) as a parameter of vascular aging in all of these patients.
Results: CD57⁺ or CD28^null fraction in CD8 T cell subset correlated with age and PWV (p<0.001 for all). Patients with hypertension exhibited significantly higher CD28^null fraction in CD8 T cell subset than age, sex-matched control subjects (46.1 짹 13.0 % vs. 29.8 짹 18.7 %, p=0.036). In subgroup analysis, the CD57⁺ or CD28^null fraction in CD8 T cell subset was independently associated with the PWV after adjusting age, sex, and brachial systolic blood pressure in patients with hyperlipidemia (CD57⁺: r²=0.178, p=0.010; CD28^null: r²=0.114, p=0.011).
Conclusion: CD57⁺ or CD28^null fraction in CD8 T cell subset is independently associated with PWV result in patients with hyperlipidemia. Functional characteristics and antigen reactivity of these immunosenescent T cells need to be further investigated.