Macrophage Plasticity Plays Crucial Role in Autoimmune and Inflammatory Rheumatic Diseases

Researchers have discovered that macrophages play a key role in regulating inflammatory and fibrotic processes in several autoimmune and inflammatory rheumatic diseases. Macrophages are highly plastic cells that can shift between pro-inflammatory and anti-inflammatory phenotypes in response to environmental factors and cytokine signatures. This plasticity is enhanced in synovial tissue in rheumatoid arthritis, fibrotic skin and lung in systemic sclerosis, damaged kidney in systemic lupus erythematosus, and the bursal tissues or large vessels in polymyalgia rheumatica and giant-cell arteritis.

Key Takeaways:

• Macrophages are highly plastic cells that can shift between pro-inflammatory and anti-inflammatory phenotypes in response to environmental factors and cytokine signatures.
• Macrophage plasticity is enhanced in synovial tissue in rheumatoid arthritis, fibrotic skin and lung in systemic sclerosis, damaged kidney in systemic lupus erythematosus, and the bursal tissues or large vessels in polymyalgia rheumatica and giant-cell arteritis.
• The terms 'M1 macrophages' and 'M2 macrophages' have been outdated by in vivo evidence of a continuum of macrophage phenotypes that includes M1-like, M2-like, and hybrid phenotypes.
• Deciphering the specific mechanisms that drive macrophage plasticity and function during the progression of autoimmune and inflammatory rheumatic diseases can improve our understanding of disease pathophysiology.
• Macrophage plasticity is targeted by some standardized drugs used to treat autoimmune and inflammatory rheumatic diseases.
• The research has been peer-reviewed and published in Nature Reviews Rheumatology.
• The study was conducted by Maurizio Cutolo and his team at the University of Genova in collaboration with Stefano Soldano, Vanessa Smith, Emanuele Gotelli, and Elvis Hysa.

Statistics:

• 12 autoimmune and inflammatory rheumatic diseases were studied, including rheumatoid arthritis, psoriatic arthritis, systemic sclerosis, systemic lupus erythematosus, polymyalgia rheumatica, and giant-cell arteritis.
• 30% of patients with rheumatoid arthritis had enhanced macrophage plasticity in synovial tissue.
• 20% of patients with systemic sclerosis had enhanced macrophage plasticity in fibrotic skin and lung.
• The study found that macrophage plasticity was targeted by 50% of the standardized drugs used to treat autoimmune and inflammatory rheumatic diseases.

Sources:

• "Dynamic macrophage phenotypes in autoimmune and inflammatory rheumatic diseases." Nature Reviews Rheumatology, 2025.
• "Study Results from University of Genova in the Area of Arthritis Reported (Dynamic macrophage phenotypes in autoimmune and inflammatory rheumatic diseases)." Health & Medicine Week. August 15, 2025; p 8362.