Cytokine expression in circulating T lymphocytes from patients undergoing carotid endarterectomy

Aim. We investigated a possible relationship of cytokine expression and phenotype features of circulating T lymphocytes with the histological type of atherosclerotic plaque removed during carotid endarterectomy. Methods. Peripheral blood samples were taken from 20 patients with carotid atherosclerosis and from 8 healthy blood donors. Patients were divided into 2 groups according to the histological type of their atherosclerotic plaques (types V and VI). Expression of intracellular tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin-4 (IL-4), and of surface antigens (CD4, CD8, CD45RA, CD45RO, T cell receptor (TCR) alpha/beta, TCR 7/5) in circulating T lymphocytes was determined by 3-colour cytofluorimetric analysis. Results. The percentage of T lymphocytes primed for TNF-alpha, IFN-gamma and IL-4 was higher in blood samples from patients than from healthy subjects; the difference was statistically significant for TNF-alpha-producing cells (p=0.01). In patients, the percentage of TNF-alpha-producing cells was significantly higher in the CD4(+) subset than in the CD8(+) subset (p=10(-4)). The percentage of TNF-alpha-, IFN-gamma- and IL-4-primed cells was higher in patients with type VI plaques (complicated lesions) than in patients with type V plaques (less complicated lesions). The difference was statistically significant for TNF-alpha-primed cells (P=0.05). No statistically significant differences were found in T cell phenotype features among patients or between patients and healthy subjects. Conclusion. Our results suggest a relationship between the percentage of circulating T lymphocytes expressing TNF-a and possibly IFN-gamma and IL-4 and the histological type of atherosclerotic plaque in patients with carotid artery disease.