A new development in MS

We have a better understanding of why MS can get worse without recent relapses or MRI activity. This new understanding of the chronic smoldering process and how it causes disability progression is inspiring a new era of MS research.

Understanding MS: the 2 processes

The acute processA process in MS that causes damage quickly, leading to relapses and MRI activity. has been well understood for years—it primarily causes relapsesAn event during which MS symptoms temporarily get worse or new symptoms appear, followed by a remission, during which symptoms usually improve. Relapses are associated with the acute process. Also known as: flare-ups, attacks. and MRI activityAreas of inflammation and/or damage in the central nervous system that healthcare providers can see on magnetic resonance imaging, also known as an MRI.. The evolving science of MS is around understanding how the chronic smoldering processA process that happens only in the brain and is ongoing from the start of MS. This process slowly causes damage that results in disability progression. Also known as: compartmentalized inflammation, chronic progressive process, smoldering MS, smoldering neuroinflammation. leads to disability progressionA gradual increase or worsening of physical symptoms, cognitive symptoms and/or fatigue over time.. Both the chronic smoldering process and the acute process can be happening at the same time but can affect you in different ways:

Graph of MS progression over time, showing the acute process decreasing over time and the chronic smoldering process starting early and increasing over time, causing disability progression

Watch the video to learn about the science behind the 2 processes:

How do the 2 processes work?

“Illustration showing acute and chronic smoldering MS processes: shows the acute process of activated B and T cells crossing the blood brain barrier, causing relapses and MRI activity, and the chronic smoldering process of activated microglia causing disability progression

The chronic smoldering process can gradually cause damage to the brain and spinal cord, which leads to disability progression. This process begins before the first symptoms are noticed and causes disability to slowly build up over time.

A new focus of MS research

There's an enzymeA protein that triggers a chemical reaction in your body. For example, an enzyme may activate B cells and microglia. called Bruton’s Tyrosine Kinase (BTK)An enzyme that activates both B cells and microglia. In people with MS, this activation can lead to damage. that plays a role in both processes:

Acute process:

B cellsTypes of cells that can be found in the bloodstream and work as part of the immune system. During the acute process of MS, these cells enter the brain and cause damage to myelin. are activated by BTK to cause damage, resulting in relapses and MRI activity

Chronic smoldering process:

MicrogliaCells that are a part of the immune system and are only found in the brain and spinal cord. During the chronic smoldering process in MS, activated microglia can cause damage to myelin, brain cells and other areas of the brain. are activated by BTK, which may lead to disability progression

Image of a woman looking at the sky with a telescope”

A new era of MS research is on the horizon

Today's MS therapies have come a long way in how they treat the acute process to control relapses and MRI activity. But many people with MS still experience disability progression. That means there's more to address when it comes to the chronic smoldering process.

Today's therapies are unable to do both of the things that are believed to address the chronic smoldering process:

Get inside the brain where the process happens
Make a meaningful impact on microglia, a cell involved in the process

This important understanding of the chronic smoldering process is inspiring a new era of MS research.

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