om Bochum observed a patient with chronic Hepatitis E infection over a year. Repeated sequencing of the virus RNA showed that the virus incorporated various parts of the host’s messenger RNA into its genome. This resulted in a replication advantage, which may have contributed to the infection becoming chronic.From Bochum, a patient with long-term Hepatitis E infection was studied for a year. The virus RNA was repeatedly sequenced and it was found that the virus had incorporated different parts of the patient’s messenger RNA into its genome. This gave the virus an advantage in replication, potentially leading to the development of chronic infection. Dr. Daniel Todt, from the Computational Virology research group at Ruhr University Bochum, Germany, stated that the insertion of host RNA could potentially indicate the transition from acute infection to a chronic condition. These findings were reported in the journal “Nature Communications”.
Virus Population Sequencing
Each year, approximately 20 million individuals worldwide are affected by Hepatitis E. While the infection typically resolves on its own, it can pose a serious threat to pregnant women and those with weakened immune systems. In some instances, the infection becomes chronic, and there are currently no specific effective treatments available. Although the antiviral drug Ribavirin is used to combat Hepatitis E, it is not always successful.
The researchers sought to determine how the virus is able to evade the immune system and why the infection can become chronic rather than heal.
Researchers have studied and analyzed all virus populations from a chronically infected patient for over a year. They carefully examined over 180 individual sequences from blood samples.
Benefits of Host RNA in Cell Culture Replication
“The Hepatitis E virus has a hypervariable region in its genetic information, where it can incorporate various RNA sequences from host cells,” explained Daniel Todt. His team found that the composition of this region changed significantly during the observation period. Furthermore, multiple different compositions occurred simultaneously.
In cell culture studies, it was found that adding host RNA gave the virus a replication advantage: The modified viruses were able to replicate more effectively than others. “We believe that this is partly responsible for the infection becoming long-lasting and the treatment being unsuccessful,” Daniel Todt explains. The scientists analyzed the makeup of the host RNA integrated into the virus to see if there were any shared characteristics among the gene segments. “However, we were unable to find any significant similarities,” Todt says. The integrated gene sequences mostly consist of those that are commonly found in host cells, suggesting a random selection.
“It is possible that during Hepatitis E infection, there is a competition between the virus and the immune system in the body,” said Daniel Todt. If the virus is able to integrate host RNA before the immune system can effectively fight the infection, it could result in a chronic course. “The presence of host RNA in the viral genome could potentially be used as a biomarker in the early stages of an infection, indicating the likelihood of it becoming chronic.”
The researchers intend to broaden their studies to include larger groups of patients.
