Editorial: Defining the Functional Diversity of Synovial Macrophages

By
Anna B. Montgomery
Deborah R. Winter
June 30, 2026

Frontiers In Immunology

Overview

This editorial discusses the functional heterogeneity of synovial macrophages and their roles in joint homeostasis and inflammation.

Background

Macrophages are crucial for tissue homeostasis and respond to inflammation by differentiating from peripheral blood monocytes. In the synovium, their location correlates with specific functions, making it essential to understand their diversity in relation to joint diseases such as rheumatoid arthritis and osteoarthritis.

Data Highlights

No numerical data provided in the source material.

Key Findings

Synovial macrophages exhibit divergent functions influenced by local and systemic signals.
Age and sex affect the transcriptional profiles of synovial macrophages, with notable differences observed between males and females.
In aging females, there is an increase in Arg1-expressing MHCII+ macrophages, while aging males show a decrease.
RELMα+ interstitial macrophages are positioned near blood vessels and are key in recruiting monocytes during inflammatory arthritis.
Pyroptosis, a form of inflammatory cell death, may play a role in the pathogenesis of osteoarthritis.

Clinical Implications

Understanding the functional diversity of synovial macrophages can inform strategies for targeting inflammatory joint diseases. Recognizing sex and age-related differences in macrophage behavior may lead to more personalized approaches in treatment.

Conclusion

The editorial emphasizes the complexity of synovial macrophage functions and their implications for joint health, particularly in the context of aging and sex differences.