MACROPHAGE ACTIVATION SYNDROME
What happens in the body?
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How macrophage activation syndrome (MAS) works
MAS is a secondary condition, which means it can be triggered by other existing medical problems, such as infection or rheumatic disease, like sJIA or Still's disease. Like the name describes, MAS happens when the body's immune system isn't working properly and activates too many defensive cells called macrophages (pronounced MACK-ROW-FAY-JIS), which results in dangerous amounts of inflammation in the body. This is called hyperinflammation.
To understand more about MAS, first let’s see how a healthy immune system works:
During an attack from harmful cells, immune-system cells named T cells look for and destroy harmful cells.
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When harmful cells are present in the body, immune cells work to destroy them. These immune cells are called T cells.
To do their job, T cells need help from other immune cells.
T cells send out messenger proteins called cytokines (pronounced SIGH-TOE-KINES).
When harmful cells are present in the body, immune cells work to destroy them. These immune cells are called T cells.
To do their job, T cells need help from other immune cells.
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T cells send out messenger proteins called cytokines (pronounced SIGH-TOE-KINES).
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Inflammation is part of the body's healthy, controlled response to harmful cells.
How does MAS cause hyperinflammation?
In an immune system experiencing MAS in Still's:
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Since so many macrophages are activated, the condition is called macrophage activation syndrome, or MAS.
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Since so many macrophages are activated, the condition is called macrophage activation syndrome, or MAS.
T cells don’t work properly. They send out too many cytokines, including interferon gamma (IFNγ).
Too much IFNγ activates an increasing number of macrophages.
So many cytokines and macrophages result in dangerous amounts of
inflammation.
High amounts of inflammation are called "hyperinflammation."
Hyperinflammation can damage organs such as the heart, liver, spleen, and kidneys.
Hyperinflammation can damage organs such as the heart, liver, spleen, and kidneys.
When MAS in Still's strikes, it may often be confused with a flare of sJIA or Still’s. It’s important to know the symptoms of MAS to look for.
