Amphotericin B lowers defence against Influenza

Having Influenza can be life-threatening but you can effectively protect yourself by getting your yearly vaccination. If you need chemotherapy or a bone marrow transplant, the last thing you want to catch is the flu.

Now, scientists are worried about Amphotericin B, a powerful anti-fungal drug commonly used intravenously to treat severe fungal infections that can occur in many critically ill patients needing chemotherapy or a bone marrow transplant.

The research indicates[1] that Amphotericin B may be interfering with the way the body defends itself against an infection with the Influenza virus. The effect was already known[2] to occur in vitro. Previous research had also shown that a protein called IFITM3 restricts the Influenza virus. Mice that are unable to produce the protein are more vulnerable to infection and will have more severe symptoms. The findings suggest that Amphotericin B destroys IFITM3 and leaves mice susceptible to Influenza.

Prof Abraham Brass, from the University of Massachusetts Medical School, said: "We now see that a major part of the body's natural defences to influenza virus is rendered inactive by Amphotericin B”.

The findings raised the priority for vaccinating such vulnerable patients against seasonal Influenza.

[1] Tsai-Yu Lin et al: Amphotericin B Increases Influenza A Virus Infection by Preventing IFITM3-Mediated Restriction in Cell Reports - 2013
[2] Roethl et al: Antimycotic-antibiotic amphotericin B promotes influenza virus replication in cell culture in Journal of Virology - 2011