09 Oct 2023
Antibody-based therapy trial shows promise in patients with influenza B
Antibody-based therapies for respiratory viruses are a safe and effective tool to treat severe respiratory infections. However, researchers across the globe have faced challenges in the development of antibody-based treatments for influenza, with clinical trials generally showing limited or no impact on influenza A. Today, there are currently no approved antibody-based therapies to treat human influenza.
A collaboration of researchers from the Doherty Institute, the Kirby Institute and institutions around the world studied the effect of injected Intravenous Immunoglobulin for Influenza (Flu-IVIG), antibodies from the blood of individuals who have been exposed to or vaccinated against the influenza virus, in people hospitalised with severe influenza, and revealed valuable insights on the complex mechanisms underlying antibody-based therapies for these patients.
The team led by Dr Hillary Vanderven, former PhD researcher at the Doherty Institute and now Immunologist at James Cook University, examined the findings of a recent international clinical trial. The trial found that treatment with Flu-IVIG (anti-influenza hyperimmune intravenous immunoglobulin, a concentrated solution of antibodies) improved outcomes in patients hospitalised with influenza B, but didn't provide clinical benefits to patients with influenza A.
Dr Vanderven explained that, in a new study published in JCI Insight, the team leveraged the findings from that clinical trial and set out to understand why Flu-IVIG treatment was only effective against influenza B.
“Our findings suggest that certain types of influenza antibodies that are capable of killing infected cells, may assist in recovery from severe influenza B but not influenza A,” she said.
“Improved outcomes in patients with influenza B were associated with a specific group of antibodies when they were present in greater quantities. Additionally, Flu-IVIG proved beneficial for individuals with low levels of anti-influenza B antibodies.
“However, we were surprised to discover that higher levels of these same antibodies were associated with poorer outcomes in patients with influenza A, and Flu-IVIG didn't benefit those with low levels of anti-influenza A antibodies.”
University of Melbourne Professor Stephen Kent, a Laboratory Head at the Doherty Institute and the senior author of the paper, said the lack of clinical benefits from antibody treatment on patients with influenza A could be due to a number of factors.
“Understanding the intricate balance between the protective and the potentially harmful roles of the antibodies in the immune system is very complex, but crucial,” said Professor Kent.
“Things like the type of influenza virus, clinical presentation and the patient’s immunological history may impact on the antibodies’ functions and their ability to kill influenza-infected cells. This is something that needs to be further investigated.
“This work provides clues on how to tailor treatments and vaccines for different types of influenza and is a significant step towards understanding immunity to influenza.”
Peer review: JCI Insight (DOI: https://doi.org/10.1172/jci.insight.167464)
Funding: National Health and Medical Research Council (NHMRC)