Overlapping macrophage immune profiles in polymyalgia rheumatica and giant cell arteritis
Anqi Zhang1, William F Jiemy1, Yannick van Sleen1
1Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.
Objective:
Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are closely related chronic inflammatory diseases in which macrophages play a central role in the pathogenesis. This study compared macrophage-related immune profiles in subacromial bursal tissues affected by PMR and temporal arteries affected by GCA to identify shared therapeutic targets.
Methods:
Subacromial bursa biopsies (SABBs) were obtained from patients with active PMR (n = 11). Temporal artery biopsies (TABs) were collected from 14 patients with GCA. Immunohistochemical staining was performed for macrophage markers [CD68, CD64, CD86, CD206 and folate receptor (FR) β] and macrophage-related cytokines (GM-CSF, IL-6, IL-23, IFN-γ, M-CSF and TNF-α). The percentage of positively stained cells was quantitatively scored.
Results:
All macrophage-related markers and cytokines were expressed in both PMR-affected SABBs and GCA-affected TABs. The proportions of cells expressing macrophage markers (CD68, CD64, CD86 and CD206) and macrophage-related cytokines (GM-CSF, IL-6, IL-23, IFN-γ, M-CSF and TNF-α) were comparable between the two tissue types. However, the expression of FRβ was relatively higher in GCA TABs than in PMR SABBs.
Conclusion:
The macrophage immune profiles are remarkably similar in PMR SABBs and GCA TABs. This study underscores the concept of PMR and GCA as a disease spectrum and identifies shared therapeutic targets for both PMR and GCA.
Insights
Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) share similar macrophage immune profiles in affected tissues. This suggests they may be part of a disease spectrum, offering potential shared therapeutic targets for both inflammatory conditions.
Area of Science:
- Rheumatology
- Immunology
- Pathology
Background:
- Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are chronic inflammatory conditions.
- Macrophages are key players in the pathogenesis of both PMR and GCA.
- Understanding shared immune profiles can reveal common therapeutic strategies.
Purpose of the Study:
- To compare macrophage-related immune profiles in PMR-affected subacromial bursa and GCA-affected temporal artery tissues.
- To identify potential shared therapeutic targets for PMR and GCA.
Main Methods:
- Biopsies from PMR patients' subacromial bursa (SABBs) and GCA patients' temporal arteries (TABs) were analyzed.
- Immunohistochemical staining was used to assess macrophage markers (CD68, CD64, CD86, CD206, FRβ) and cytokines (GM-CSF, IL-6, IL-23, IFN-γ, M-CSF, TNF-α).
- Quantitative scoring assessed the expression levels of these markers and cytokines.
Main Results:
- Macrophage markers and cytokines were expressed in both PMR SABBs and GCA TABs.
- The proportions of cells expressing most macrophage markers and cytokines were comparable between PMR and GCA tissues.
- Folate receptor beta (FRβ) expression was higher in GCA TABs compared to PMR SABBs.
Conclusions:
- Macrophage immune profiles in PMR and GCA tissues are highly similar.
- PMR and GCA can be viewed as part of a disease spectrum.
- The findings highlight shared therapeutic targets for both polymyalgia rheumatica and giant cell arteritis.
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