Testing 18F-DPA-714 PET scan as a marker of brain inflammation in patients with autoimmune encephalitis

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What is this study about?

This study is looking at autoimmune encephalitis, which is a condition where the body’s immune system mistakenly attacks the brain, causing inflammation. This can lead to various problems with thinking, memory, behavior, and movement. The study will use a special imaging substance called 18F-DPA-714, which is given as an injection into a vein. This substance is used during a type of brain scan called PET, which stands for positron emission tomography. The scan helps doctors see areas of inflammation in the brain by showing where certain cells that are involved in inflammation are active.

The purpose of the study is to see if this type of scan can be a good way to detect and measure brain inflammation in people with autoimmune encephalitis by comparing the scan results from patients to those from healthy people. During the study, participants will receive the imaging substance through an injection and then have a brain scan. The scan will measure how much of the substance attaches to specific areas in the brain, which indicates where inflammation might be present. The study will look at the whole brain as well as specific regions to understand the pattern of inflammation.

Researchers will compare the scan results between patients with autoimmune encephalitis and healthy individuals to see if there are clear differences. They will also look at whether the scan results match with other tests that are commonly used to diagnose this condition, such as blood tests, spinal fluid tests, and other types of brain scans. The study will examine if the amount of inflammation seen on the scan relates to how severe the symptoms are and whether certain brain regions showing inflammation correspond to specific symptoms that patients experience.

1 Initial assessment and confirmation

Your participation in this study will begin after confirmation that you meet the required criteria. This includes being between 18 and 80 years of age, having a diagnosis of autoimmune encephalitis (a condition where the immune system mistakenly attacks the brain) with identified antibodies, and having symptoms for less than 6 months.

A test will be performed to determine your TSPO binding affinity phenotype. This is a genetic characteristic that affects how certain imaging substances bind to proteins in your brain. Only individuals with high or mixed binding affinity will continue in the study.

You should not have received second-line immunosuppressive treatment (advanced medications that suppress the immune system) prior to entering the study.

2 PET scan preparation

You will undergo a PET scan (Positron Emission Tomography), which is an imaging procedure that creates detailed pictures of your brain activity.

Before the scan, you will receive an injection of a radioactive tracer called 18F-DPA-714. This substance is administered through intravenous injection (into a vein).

The tracer is designed to bind to areas of inflammation in your brain, allowing doctors to see where inflammation is present.

3 PET scan procedure

After receiving the 18F-DPA-714 injection, you will undergo the PET scanning procedure.

During the scan, you will lie still while the scanner takes images of your brain. The tracer will help identify areas of neuroinflammation (inflammation in the nervous system).

The scan will measure the binding potential of the tracer throughout your brain. This measurement indicates how much inflammation is present in different brain regions.

4 Clinical assessments

You will undergo clinical severity assessments to evaluate your symptoms and their impact.

Other standard diagnostic tests for autoimmune encephalitis will be performed. These may include blood tests, spinal fluid analysis, and other imaging studies that are routinely used to diagnose this condition.

These assessments will help doctors understand the relationship between the PET scan results and your clinical condition.

5 Data analysis and comparison

Your PET scan results will be analyzed using an automated clustering method to calculate the binding potential across your entire brain.

Your results will be compared to those of healthy control participants to determine if there are significant differences.

The analysis will examine both your whole brain and specific regions of interest to identify areas with increased inflammation.

Your scan will be classified as either positive or negative based on whether any brain region shows binding potential greater than 2 standard deviations above the average of control participants.

Who Can Join the Study?

You must be between 18 and 80 years old.
You must meet the medical criteria for possible autoimmune encephalitis, which is a condition where the body’s defense system mistakenly attacks the brain, and specific antibodies (proteins made by your immune system) have been found in your blood or spinal fluid.
You must have been newly diagnosed with symptoms that started less than 6 months ago.
You must not have received second-line immunosuppressive treatment, which means you have not yet been given stronger medications that work to calm down your immune system beyond the first basic treatments.
You must have a high or mixed TSPO binding affinity phenotype, which is a specific genetic trait that affects how certain proteins in your body respond to the imaging scan used in this study. This will be determined through testing.

Who Cannot Join the Study?

The study does not list specific reasons why a patient cannot participate at this time
General safety rules for medical imaging studies may apply, such as pregnancy or breastfeeding, which means nursing a baby
People who cannot tolerate lying still during the scan may not be able to participate
Those with allergies, which are bad reactions to certain substances, to the imaging tracer used in the study may be excluded
Patients who have received other experimental treatments recently may not be eligible
Those with serious medical conditions affecting other organs may not qualify for participation

Where you can join this trial?

Verified and Recommended Sites

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Verified Sites

Site Name	City	Country	Status
Oncopole Claudius Regaud	Toulouse	France

Other Sites

No sites found in this category

Trial status

Country	Status	Recruitment Start
France	Recruiting	22.12.2025

Trial locations

[18F]-DPA-714 is a radioactive tracer used during a PET scan (a type of medical imaging test). This substance helps doctors see and measure inflammation in the brain. It works by attaching to specific proteins that appear when there is inflammation, allowing the scanner to create detailed images that show where inflammation is occurring in the brain.

Investigated diseases:

Encephalitis autoimmune

Autoimmune Encephalitis – Autoimmune encephalitis is a condition where the body’s immune system mistakenly attacks healthy brain cells, causing inflammation of the brain. This inflammation can develop rapidly over days to weeks, or more gradually over several months. The disease affects various brain functions, leading to changes in behavior, memory problems, confusion, and difficulties with thinking. People with this condition may experience seizures, unusual movements, or psychiatric symptoms such as hallucinations or paranoia. Sleep disturbances and speech problems can also occur as the disease progresses. The symptoms vary depending on which parts of the brain are affected by the immune system’s attack.

Trial ID:

2025-522768-33-00

Protocol code:

RC31/24-0569

Trial Phase:

Therapeutic exploratory (Phase II)

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Testing 18F-DPA-714 PET scan as a marker of brain inflammation in patients with autoimmune encephalitis

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