Chemokine receptor expression on infiltrating lymphocytes from abdominal aortic aneurysms: Role of CXCR4–CXCL12 in lymphoid recruitment

This is a study to define the profile of chemokine receptors expressed on isolated infiltrating lymphocytes in human abdominal aortic aneurysms (AAAs), and to examine their role in lymphoid recruitment. AAA T-lymphocytes were CXCR4-positive, CCR7-negative and partially CXCR3 and CCR5-positive. Functionally, AAA T-cells were proinflammatory effector cells, as they produced IFN-γ and granzyme A. AAA B-lymphocytes were CXCR4-positive and exhibited low CXCR5 expression. A relevant feature of infiltrating T- and B-lymphocytes was the high intensity of CXCR4 expression and the capability to migrate to CXCL12. CXCL12-producing cells were found in the adventitia of AAA. These cells were CD45-negative and partially VCAM-1 and DR-positive. In summary, the present results suggest that CXCR4, expressed on infiltrating lymphocytes, and CXCL12, expressed on stromal cells, is involved in the recruitment of lymphocytes within the arterial wall in AAA.