Summary: Higher levels of immune proteins are present in the blood before and after an epileptic seizure. The researchers say the biomarkers can be identified via a simple blood test.
Source: Lund University
Researchers from Lund University in Sweden have found higher levels of immune proteins in the blood before and after an epileptic seizure. Possible biomarkers can be identified using a simple blood test.
Diagnosing epilepsy is currently resource intensive and it can be difficult to distinguish it from other conditions. Better diagnostic methods as soon as the patient consults after a suspected attack are therefore urgently needed.
Epilepsy is the collective name for abnormal brain activity that results in a temporary loss of control of behavior and movement. The disease can be congenital, caused by a tumor, stroke, or brain infection, and cause very different symptoms depending on which part of the brain the episode begins or spreads to. Inflammatory processes that begin with an immune response in the body can also cause an attack.
That’s why researchers started looking for possible biomarkers of epilepsy within the immune system. Previous studies exist, but the results so far are mixed and difficult to interpret:
“In our study, we have a carefully selected group of participants and we have a lot of background information about each person. We also took into account a number of confounding factors that can affect the immune system, such as other neurological and immunological diseases, infections and various psychiatric conditions,” explains Christine Ekdahl Clementson.
She is group leader and associate professor at Lund University and consultant in clinical neurophysiology at Skåne University Hospital. She focuses on advanced epilepsy investigations and she led the research study. The research team also compared epileptic seizures to what are called psychogenic non-epileptic seizures.
Psychogenic seizure is a psychiatric diagnosis manifested by clinical symptoms that can easily be confused with epilepsy. It is a chronic disease that is thought to be underdiagnosed and therefore often mistakenly treated with anti-epileptic drugs. This is why there is a great need to be able to more easily distinguish the conditions.
“The investigation to determine if a person has epilepsy or is affected by psychogenic seizures is resource intensive. This may require the patient to be hospitalized for several days with constant video and EEG monitoring, with medical staff available 24 hours a day. It is hard on the patient that it takes time to arrive at a diagnosis,” explains Marie Taylor, doctor and doctoral student in the research team.
The researchers found that levels of five markers of inflammation, proteins, were acutely elevated in people who had suffered an epileptic seizure.
“We call these markers ‘fingerprints’ because they involve several inflammation-related proteins with different reaction patterns. Epilepsy patients showed elevated levels of one of the five proteins – IL-6 – even before their seizures, a value that transiently increased even more directly after the seizure,” says Marie Taylor.
Among patients with psychogenic seizures, however, there was no change in biomarkers. This could mean that a simple blood test on a patient arriving at A&E after a seizure can show whether the immunological response is high. If not, it is more likely to be a psychogenic crisis, which provides a first indication of how the patient should be further assessed.
“The next step is to repeat our studies on a larger and less homogeneous group of patients, where we study the “fingerprints” in adults with epilepsy. We also want to see if the biomarkers respond the same way in children, where the causes of epilepsy are more often genetic.
“We are doing this through an ongoing study in Lund, in collaboration with child and adolescent psychiatry and pediatric neurology,” concludes Christine Ekdahl Clementson.
About this epilepsy research news
Author: Press office
Source: Lund University
Contact: Press Office – Lund University
Picture: Image is in public domain
Original research: Free access.
“Immune Response in the Blood Before and After Nonepileptic Epileptic and Psychogenic Seizures” by Matilda Ahl et al. hellion
Immune response in the blood before and after non-epileptic epileptic and psychogenic seizures
- Elevated Serum IL-6 Levels in Patients with Temporal and Frontal Epilepsy
- Altered postictal-interictal ratio of immune factors in serum after temporal lobe but not frontal lobe seizures
- No change in serum IL-6 levels in patients with non-epileptic psychogenic seizures
Inflammatory processes can cause epileptic seizures, and seizures can promote an immune reaction. Therefore, the systemic immune response is a tempting diagnostic and prognostic marker in epilepsy.
We explored the immune response before and after epileptic and psychogenic non-epileptic (PNES) seizures. Serum samples collected from patients with temporal or frontal epilepsy verified by videoEEG (TLE or FLE) or TLE + PNES showed increased interleukin-6 (IL-6) levels between seizures (interictal ), compared to controls.
Patients with PNES did not have an increase in IL-6. IL-6 levels transiently increased even more within hours of an attack (postictally) in TLE patients but not in FLE patients. The postictal to interictal ratio of five additional immune factors was also increased in TLE patients only.
We conclude that immune factors have the potential to be future biomarkers for epileptic seizures and that heterogeneity between different epileptic and non-epileptic seizures can be revealed in peripheral blood sampling independently of comorbidities.