Lymphocyte Subpopulations in Lymph Nodes and Peripheral Blood: A Comparison between Patients with Stable Angina and Acute Coronary Syndrome

Abstract

ObjectiveAtherosclerosis is characterized by a chronic inflammatory response involving activated T cells and impairment of natural killer (NK) cells. An increased T cell activity has been associated with plaque instability and risk of acute cardiac events. Lymphocyte analyses in blood are widely used to evaluate the immune status. However, peripheral blood contains only a minor proportion of lymphocytes. In this study, we hypothesized that thoracic lymph nodes from patients with stable angina (SA) and acute coronary syndrome (ACS) might add information to peripheral blood analyses.MethodsPeripheral blood and lymph nodes were collected during coronary by-pass surgery in 13 patients with SA and 13 patients with ACS. Lymphocyte subpopulations were assessed by flow cytometry using antibodies against CD3, CD4, CD8, CD19, CD16/56, CD25, Foxp3, CD69, HLA-DR, IL-18 receptor (R) and CCR4.ResultsLymph nodes revealed a lymphocyte subpopulation profile substantially differing from that in blood including a higher proportion of B cells, lower proportions of CD8+ T cells and NK cells and a 2-fold higher CD4/CD8 ratio. CD4+CD69+ cells as well as Foxp3+ regulatory T cells were markedly enriched in lymph nodes (p<0.001) while T helper 1-like (CD4+IL-18R+) cells were more frequent in blood (p<0.001). The only significant differences between ACS and SA patients involved NK cells that were reduced in the ACS group. However, despite being reduced, the NK cell fraction in ACS patients contained a significantly higher proportion of IL-18R+ cells compared with SA patients (p<0.05).ConclusionThere were several differences in lymphocyte subpopulations between blood and lymph nodes. However, the lymphocyte perturbations in peripheral blood of ACS patients compared with SA patients were not mirrored in lymph nodes. The findings indicate that lymph node analyses in multivessel coronary artery disease may not reveal any major changes in the immune response that are not detectable in blood.

Functional and homeostatic defects of regulatory T cells in patients with coronary artery disease

“…We recently measured the proportions of Tregs in thoracic lymph nodes from patients undergoing coronary bypass surgery. The levels of total Tregs in lymph nodes were found to be twofold higher than in blood independent of whether patients had a diagnosis of ACS or stable CAD , but nTreg and mTreg fractions were not investigated. It remains a possibility that the low levels of circulating mTregs are at least partly due to a redistribution of these cells to lymphoid tissues.…”

Interplay of NK cells and monocytes in vascular inflammation and myocardial infarction

“…This effect was much more pronounced in patients in unstable conditions or acute coronary syndrome (Backteman et al, 2012; Hou et al, 2012). …”

“…However, failure to reconstitute NK cell levels was associated with a persistent low-grade inflammation, suggesting a protective role of NK cells in CAD (Backteman et al, 2012). The mechanism why there is a deficit of NK cells in CAD is not identified yet, but an increased apoptosis of these cells in CAD patients has been reported (Li et al, 2008).…”

Role of Lymphocytes in Myocardial Injury, Healing, and Remodeling After Myocardial Infarction

“…A comparative analysis of thoracic lymph nodes from patients with ACS and stable angina undergoing cardiac bypass surgery failed to find differences between the 2 cohorts' lymph node cellular composition. 87 Thus, more data on T-cell activation and differentiation parameters from human tissue specimen would be highly valuable in deciphering the role of lymphocytes after MI.…”