Tissue-specific Role of CX₃CL1 Expressing Immune Cells and Their Relationships with Human Disease

Chemokine (C-X3-C motif) ligand 1 (CX₃CL1, also known as fractalkine) and its receptor chemokine (C-X3-C motif) receptor 1 (CX₃CR1) are widely expressed in immune cells and non-immune cells throughout organisms. However, their expression is mostly cell type-specific in each tissue. CX₃CR1 expression can be found in monocytes, macrophages, dendritic cells, T cells, and natural killer (NK) cells. Interaction between CX3CL1 and CX₃CL1 can mediate chemotaxis of immune cells according to concentration gradient of ligands. CX₃CL1 expressing immune cells have a main role in either pro-inflammatory or anti-inflammatory response depending on environmental condition. In a given tissue such as bone marrow, brain, lung, liver, gut, and cancer, CX₃CL1 expressing cells can maintain tissue homeostasis. Under pathologic conditions, however, CX₃CL1 expressing cells can play a critical role in disease pathogenesis. Here, we discuss recent progresses of CX3CL1/CX₃CL1 in major tissues and their relationships with human diseases.

Comparison of Non-invasive Imaging Studies in the Evaluation of Carotid Artery Stenosis and Occlusion: CT Angiography, Time-of-Flight MR Angiography and Contrast-Enhanced MR Angiography

PURPOSE: We compared non-invasive imaging studies of CTA, TOF-MRA and CE-MRA to evaluate detecting internal carotid artery stenosis and occlusion. MATERIALS AND METHODS: We enrolled 20 patients with clinically suspected internal carotid artery stenosis and occlusion, or asymptomatic patient with more than 50% stenosis suspected on color Doppler ultrasonography for regular check-up. Prospectively, CTA, TOF-MRA and CE-MRA were performed, and sensitivity, specificity, positive predictive value, negative predictive value and accuracy of TOF-MRA and CE-MRA using CTA as a reference standard for detecting more than 50% stenosis were evaluated, and correlations of measured percent stenosis between 3 imaging studies were also evaluated. RESULTS: No significant difference was found between 3 imaging studies in measuring stenosis(p>0.05). Correlation coefficient was 0.932 between CTA and TOF-MRA, and 0.971 between CTA and CE-MRA. TOF-MRA had 83.3% sensitivity, 87.5% specificity, 71.4% positive predictive value, 93.3% negative predictive value and 86.4% accuracy for detecting more than 50% stenosis and occlusion. CE-MRA had 83.3% sensitivity, 93.8% specificity, 83.3% positive predictive value, 93.8% negative predictive value and 90.9% accuracy. CONCLUSION: TOF-MRA and CE-MRA provided high correlations in the evaluation of internal carotid artery stenosis and occlusion.