ACR Meeting Abstracts

ACR Meeting Abstracts

Abstract Number: 900

The Phenotype of Macrophages in the Inflamed Vascular Wall of Giant Cell Arteritis Resembles the Phenotype of Non-Classical Monocytes

Yannick van Sleen, Qi Wang, Wayel H. Abdulahad, Arjan Diepstra, Annemieke M.H. Boots and Elisabeth Brouwer, Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

Meeting: 2016 ACR/ARHP Annual Meeting

Date of first publication: September 28, 2016

Keywords: ,

Session Information

Date: Sunday, November 13, 2016

Title: Vasculitis - Poster I: Large Vessel Vasculitis and Polymyalgia Rheumatica

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 . Twelve patients were without any treatment at the time of biopsy , 4 patients started corticosteroid treatment 2-14 days before the biopsy was taken. The phenotype of macrophages in the different layers of the TAB was studied by immunohistochemistry and by double staining using immunofluorescence-labeled antibodies. Expression of chemokines in TABs was determined by digitally analyzing the diffuse positive staining. Cellular staining was assessed by semi-quantitative scoring methods.

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.

Disclosure: Y. van Sleen, None; Q. Wang, None; W. H. Abdulahad, None; A. Diepstra, None; A. M. H. Boots, None; E. Brouwer, Roche Pharmaceuticals, 5.

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 .

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