Work

Overlapping macrophage immune profiles in polymyalgia rheumatica and giant cell arteritis

Year: 2025

Type: article

Abstract: 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.

Source: Lara D. Veeken

DOI: 10.1093/rheumatology/keaf629