Evaluation of chemokine receptors (CCRs) expression on peripheral blood T-lymphocyte subsets of patients with thoracic aortic disease.

Background and aim: Histopatological investigations demonstrated an important role of the leukocyte infiltration in the evolution of the aortic valve disease (AVD) and thoracic aortic aneurysm (TAA). Moreover, the aortic size index (AI) has been correlated to the risk of aorta dissection or rupture in patients with thoracic aortic disease. In our study, we evaluated the expression level on circulating T-lymphocytes subsets of chemokine receptors (CCRs) known to be involved in T-cell homing into inflamed tissues, and we correlate it with aortic index in patients with thoracic aortic disease. Methods: Venous blood samples were obtained from 20 patients. The flow cytometry analysis was performed by appropriate combinations of monoclonal antibodies directed against the following surface molecules: CD3, CD4, CD28, CD8, TCRgamma/delta, CCR5, CXCR3, CX3CR1. Flow data were expressed in terms of percentage of positivity (positive fraction), while AI was calculated by formula: Aortic diameter/Body surface area. Results: We observed significant correlations between AI values and CCR5 expression on total CD3+ T-lymphocytes (P=0.0293) as well as on the cytotoxic CD3+/CD8+ T-cell subset (P=0.0183) (Fig. 1). An evident correlation was observed between AI and CCR5 expression on total CD4+/CD8+ T-cells (P=0.0949). Furthermore, a significant relationship (P=0.0055) was demonstrated between AI and CCR5 expression on the cytotoxic subset CD28-/CD4+ (Fig. 2). Conclusions: Our data suggest the importance of a T-cell immune-mediated cytotoxic mechanism, mainly driven by the chemokine receptor CCR5, in the progression of the thoracic aortic disease.