MAS | Macrophage Activation Syndrome

A life-threatening syndrome associated with rheumatic disease.1

Macrophage activation syndrome, or MAS, is a rare and potentially fatal syndrome that can impact many organ systems and evolve rapidly in patients with rheumatic disease.1 MAS is often associated with a range of potential triggers in the context of Still’s disease, including new onset or disease flares, and bacterial or viral infections.1

Unfortunately, signs and symptoms of this syndrome can often be confused with an underlying disease flare, making it difficult to recognize and treat in a timely fashion.1

It’s crucial to be mindful of its potential and be prepared to act for your patients with underlying rheumatic disease and patients in whom rheumatic disease has not yet been identified.1,2

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Challenges in MAS

There are significant challenges associated with managing MAS, including:

  • A need for further education on identification and prompt treatment1
  • A lack of clinically efficient biomarkers or routine lab testing that can guide management decisions3
  • Suboptimal control of MAS-driven inflammation can lead to organ damage3
  • Continued use of high-dose glucocorticoids can have damaging side effects3
  • No current FDA-approved treatments3

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References: 1. Sen ES, Clarke SL, Ramanan AV. Macrophage activation syndrome. Indian J Pediatr. 2016;83(3):248-253. doi:10.1007/s12098-015-1877-1 2. He L, Yao S, Zhang R, et al. Macrophage activation syndrome in adults: characteristics, outcomes, and therapeutic effectiveness of etoposide-based regimen. Front Immunol. 2022;13:955523. doi:10.3389/fimmu.2022.955523 3. Shakoory B, Geerlinks A, Wilejto M, et al. The 2022 EULAR/ACR points to consider at the early stages of diagnosis and management of suspected haemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS). Arthritis Rheumatol. 2023;75(10):1714-1732. doi:10.1002/art.42636