Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose: Macrophages are critical tissue destructive cells in the immunopathology of patients with giant cell arteritis (GCA). Macrophage precursors, monocytes, can be subclassified in three subsets: classical (CD14brightCD16-) monocytes and the more pro-inflammatory intermediate (CD14brightCD16+) and non-classical (CD14dimCD16+) monocytes. Tissue migration of different monocyte subsets is determined by differential expression of chemokine receptors. Our previous data showed an altered distribution of monocyte subsets in newly diagnosed GCA patients. We therefore assessed the phenotype of macrophages in temporal arteries of GCA patients. Furthermore, we investigated expression of defined chemokine receptors and their ligands in temporal arteries of GCA patients.
Methods: We studied 16 positive temporal artery biopsies (TABs), all obtained from GCA patients fulfilling the ACR 1990 criteria
Results: All GCA TABs studied showed transmural inflammation, as CD68 expressing macrophages were detected throughout the vessel wall. Non-classical monocyte markers CD16 and CX3CR1 were strongly expressed at macrophage rich areas and immunofluorescent double staining confirmed that these macrophages co-expressed CD16 and CX3CR1. CCR2, a marker of classical monocytes, was less abundantly expressed and immunofluorescent double staining confirmed that most CD16+ cells did not express CCR2. Both CCR2 ligand CCL2 and CX3CR1 ligand CX3CL1 were readily detected in the GCA TAB.
Conclusion: The phenotype of macrophages in the TAB of GCA patients resembled the phenotype of non-classical monocytes. CD16 and CX3CR1 were co-expressed on tissue macrophages therefore indicating that migration of CD16+ non-classical monocytes to the GCA lesion may be driven by the CX3CR1-CX3CL1 axis.
To cite this abstract in AMA style:van Sleen Y, Wang Q, Abdulahad WH, Diepstra A, Boots AMH, Brouwer E. The Phenotype of Macrophages in the Inflamed Vascular Wall of Giant Cell Arteritis Resembles the Phenotype of Non-Classical Monocytes [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/the-phenotype-of-macrophages-in-the-inflamed-vascular-wall-of-giant-cell-arteritis-resembles-the-phenotype-of-non-classical-monocytes/. Accessed September 19, 2019.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-phenotype-of-macrophages-in-the-inflamed-vascular-wall-of-giant-cell-arteritis-resembles-the-phenotype-of-non-classical-monocytes/