Immune system does not recover despite cured hepatitis C infection

June 11, 2018, Karolinska Institutet
Electron micrographs of hepatitis C virus purified from cell culture. Scale bar is 50 nanometers. Credit: Center for the Study of Hepatitis C, The Rockefeller University.

Changes to the immune system remain many years after a hepatitis C infection heals, a new study by researchers at Karolinska Institutet, Sweden, and Hannover Medical School, Germany, shows. The findings, presented in Nature Communications, increases understanding about chronic infection and the way it regulates and impacts composition of the immune system.

Infection with hepatitis C virus (HCV) turns almost always chronic and poses a major health problem around the world. The infection can lead to cirrhosis and cancer of the liver when the immune system fails to fight the virus. Eventually the immune system becomes exhausted. Since a couple of years, however, most patients with HCV can now be cured in a matter of a few weeks with revolutionary new medications.

The current study included 40 patients with chronic HCV infection whom researchers followed before, during and after treatment with these new medications to investigate impact on the composition and diversity of the immune system. Diversity is vital to the ability of the immune system to fight infections. Of particular importance are (NK), a type of . The researchers used flow cytometry and a new measurement method to derive the composition of the immune system, as well as the appearance of NK cells and their function in the blood.

"Researchers in the field previously focused on analysing individual components but were unable to draw any comprehensive conclusions," says Niklas Björkström, physician and associate professor at the Department of Medicine, Huddinge, Karolinska Institutet, who led the study. "The immune system is extraordinarily complex, incorporating a large number of interacting parts. We adapted new methods in order to assess and analyse that complexity in a fresh manner."

The results showed that the overall composition of the immune system was affected by the chronic infection, with significantly reduced diversity among the NK cells. Many of the changes remained long after the virus had been eliminated by means of medication. Researchers have not yet determined the long-term implications but are currently exploring whether patients have a harder time fighting future .

"One strength of our study is that we monitored patients for more than two years following elimination of the virus," says Benedikt Strunz, physician and doctoral student at the same department. "To the best of our knowledge, nobody has ever monitored over such a long term like this before."

Nevertheless, a number of questions are outstanding. Researchers would like to investigate consequences for a good deal longer than two years, as well as identify strategies for rejuvenating the immune system and increasing its diversity.

Explore further: New strategy to cure chronic hepatitis B infection

More information: Benedikt Strunz et al. Chronic hepatitis C virus infection irreversibly impacts human natural killer cell repertoire diversity, Nature Communications (2018). DOI: 10.1038/s41467-018-04685-9

Related Stories

New strategy to cure chronic hepatitis B infection

May 18, 2018
Scientists from Karolinska Institutet and Hannover Medical School have published two studies that provide insights into how the immune system responds and helps to clear a hepatitis B infection after treatment interruption. ...

Zika-related nerve damage caused by immune response to the virus

November 20, 2017
The immune system's response to the Zika virus, rather than the virus itself, may be responsible for nerve-related complications of infection, according to a Yale study. This insight could lead to new ways of treating patients ...

How viruses disarm the immune system

February 5, 2018
How do viruses that cause chronic infections, such as HIV or hepatitis c virus, manage to outsmart their hosts' immune systems?

Starved T cells allow hepatitis B to silently infect liver

May 11, 2015
Hepatitis B stimulates processes that deprive the body's immune cells of key nutrients that they need to function, finds new UCL-led research funded by the Medical Research Council and Wellcome Trust.

Key to immune system's memory revealed

December 19, 2017
Monash University's Biomedicine Discovery Institute scientists have defined a novel molecular 'blueprint' that plays a pivotal part in the immune system's ability to fight disease by 'remembering' infections. Understanding ...

Understanding immune reaction to the hepatitis B virus

November 28, 2016
A collaboration of researchers from Japan and Malaysia has further clarified the immune response to hepatitis B virus through in vivo experimentation.

Recommended for you

During HIV infection, antibody can block B cells from fighting pathogens

August 13, 2018
For the first time, scientists have shown that in certain people living with HIV, a type of antibody called immunoglobulin G3 (IgG3) stops the immune system's B cells from doing their normal job of fighting pathogens. This ...

Link between common 'harmless' virus and cardiovascular damage

August 13, 2018
Researchers from Brighton and Sussex Medical School (BSMS) have found an unexpectedly close link between a herpes virus and the occurrence of immune cells damaging cardiovascular tissue.

Single transplantation of therapeutic macrophages improves rare lung disease in mice

August 9, 2018
Hereditary pulmonary alveolar proteinosis (herPAP) is a rare disease characterized by the slow build-up of lipo-protein material in the lungs due to the failure of highly specialized cells called macrophages, which usually ...

New antibody analysis accelerates rational vaccine design

August 8, 2018
A team at Scripps Research has come up with a faster way to analyze the outcome of experimental vaccines against HIV and other pathogens. Their new system lets scientists quickly assess the full spectrum of antibodies produced ...

New immune defenders added to blood cell

August 7, 2018
Our researchers have revealed the identities of new subsets of immune cells at the frontline of our body's defenses against infection.

Striking a balance between immunity and inflammation

August 6, 2018
Hookworms infect nearly 430 million people in the world, mostly in countries where sanitation is poor, and people often walk barefoot.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.