KAIST

Liver damage becomes more severe with the decrease of regulatory T cells

“This research will aid the development of hepatitis A targeted drug,” said a KAIST researcher.

The KAIST Graduate School of Medical Science and Engineering’s Professor Eui-Cheol Shin and his research team have identified the mechanism, explaining how the regulatory T cells are responsible for the body’s immune system and how they have induced liver damage of hepatitis A patients.

The research results were published online in the July 9th edition of ‘Gut,’ the world’s most prominent journal in the field of gastroenterology.

Hepatitis A is an acute form of hepatitis caused by hepatitis A virus. The virus spreads through oral contact and enters the body via digestive organs.

Regulatory T cells play an important role in maintaining the homeostasis of the body’s immune system by inhibiting the activation of other immune cells. In the case of chronic viral infections, regulatory T cells are known to contribute to the duration of the infection, weakening the immune response to virus infections. However, there has been no information on what roles the regulatory T cells perform in the case of acute viral infections.

The research team used the fluorescence flow cytometry technique to determine the number and characteristics of a variety of immune cells, including regulatory T cells, in the blood of hepatitis A patients.

Consequently, the researchers confirmed that the decrease in the regulatory T cells immune inhibitory ability was consistent with a significant reduction in the number of regulatory T cells in the blood of hepatitis A patients. Furthermore, it was identified that the more noticeable decrease of regulatory T cells led to the occurrence of a more severe liver injury.

The analysis of hepatitis A patient’s blood proved that the cause of the decrease in the number and function of regulatory T cells was the increased expression of cell surface protein ‘Fas,’ which induces cell death.

Professor Shin said, “This study is the first case which proposes the mechanism for clinical aspects in not only hepatitis A, but also acute virus infection.” He added on the future prospect of the research that: “In the future, we can prevent tissue damage by inhibiting cell death of regulatory T cells for severe acute viral infections that do not have an effective treatment for the virus itself.”

[Picture]

The picture shows the process of fluorescence flow cytometry technique to study regulatory T cell in the blood of hepatitis A patients.