Persistent accumulation of interferon-γ-producing CD8+CD56+ T cells in blood from patients with coronary artery disease

Objective: There is emerging evidence for CD8(+) T cell alterations in blood from patients with coronary artery disease (CAD). We examined whether the distribution and phenotype of CD8(+)CD56(+) T cells differed according to the clinical manifestation of CAD. Methods: Patients with acute coronary syndrome (ACS, n = 30), stable angina (SA, n = 34) and controls (n = 36) were included. Blood was collected before and up to 12 months after referral for coronary investigation. CD8(+)CD56(+) T cells were assessed by flow cytometry for expression of surface markers, apoptosis, and intracellular expression of cytokines. Results: The proportions of CD8(+)CD56(+) T cells were significantly higher in both ACS and SA patients compared with controls, and remained so after 3 and 12 months. This was independent of age, sex, systemic inflammation and cytomegalovirus seropositivity. CD8(+)CD56(+) T cells differed from CD8(+)CD56(-) T cells in terms of lower CD28 expression and fewer apoptotic cells. Both CD8(+) T cell subsets were positive for interferon (IFN)-gamma and tumor necrosis factor, although IFN-gamma was significantly more confined to the CD8(+)CD56(+) T cells. Conclusion: The persistent accumulation of CD8(+)CD56(+) T cells in ACS and SA patients share several features with immunological aging. It also contributes to a larger IFN-gamma(+) pool in blood, and may thereby hypothetically drive the atherosclerotic process in a less favorable direction. (C) 2012 Elsevier Ireland Ltd. All rights reserved.