According to MedScape, tumor necrosis factor (TNF) inhibitors present severe issues for patients with autoimmune disorders. In particular, patients exposed to TNF inhibitors may experience inflammation throughout their central nervous system. Ultimately, this could lead to worse outcomes for patients. Find the first and second studies that developed this conclusion in JAMA Neurology.

Autoimmune Disorders

Normally, your immune system protects you against bacteria, viruses, or other foreign invaders. But for people with autoimmune disorders, the immune system mistakenly attacks parts of the body it misidentifies as being foreign. Currently, there are over 80 types of autoimmune disorders, including:

• Multiple sclerosis
• Neuromyelitis optica
• Rheumatoid arthritis
• Lupus
• Inflammatory bowel disease (IBD)
• Guillain-Barre syndrome

The Studies

According to the first study, TNF-inhibitors have been used to treat autoimmune disorders for over 30 years. Now, you might be asking yourself: What are TNF inhibitors? According to the American College of Rheumatology, TNF inhibitors:

reduce inflammation and can stop disease progression by targeting an inflammation-causing substance called Tumor Necrosis Factor (TNF).

TNF is an inflammatory protein. In individuals with no autoimmune disorders, their bodies naturally block excess TNF. But the protein can build up in the blood of those with autoimmune disorders, causing pain, inflammation, and other damage.

So, researchers wanted to understand if exposure to TNF inhibitors could increase inflammation in patients with autoimmune disorders. These inflammatory events in the central nervous system are considered demyelinating or nondemyelinating. Myelin sheaths are protective coverings of nerves. So, demyelinating inflammation damages the myelin, while nondemyelinating events do not.

Exploring TNF Inhibitors

The 2nd study followed 212 patients with various autoimmune diseases who had all been approved to use TNF inhibitors as treatment. Within the group:

• 106 patients (50%) experienced some sort of inflammatory event involving their central nervous system.
  • Of these, 56 patients experienced inflammatory demyelinating events.
    • 48 patients who experienced this had multiple sclerosis, neuromyelitis optics spectrum disorder, or transverse myelitis.
    • 8 patients had optic neuritis.
  • Of these, 50 patients experienced inflammatory nondemyelinating events.
    • 10 patients had idiopathic leptomeningitis.
    • 8 patients had aseptic meningitis.
    • 8 patients had CNS vasculitis.
    • 7 patients had autoimmune encephalitis.
    • 6 patients had idiopathic pachymeningitis.
    • 5 patients had idiopathic meningoencephalitis.
    • 4 patients had neurosarcoidosis.

Ultimately, 60% of the patients who experienced an inflammatory event were exposed to TNF inhibitors. They caused slightly more demyelinating events than nondemyelinating.

Thus, researchers determined that TNF inhibitors can increase the risk of central nervous system inflammation. However, researchers also caution that the increased risk does not mean that doctors should stop prescribing these medications. In many cases, TNF inhibitors are effective for treating autoimmune diseases.

At the same time, if doctors or patients notice the onset of new symptoms, they should consider switching medications.