Old drug may offer new way to treat flu
Updated: 2009-08-15 08:12
By Joyce Woo(HK Edition)
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HONG KONG: Researchers at the University of Hong Kong (HKU) have discovered a new treatment to combat human and avian influenza.
Researchers say the drug phosphoantigen, more commonly used to treat osteoporosis, can help fight off influenza viruses by boosting the body's immune system. They believe it will prove effective against the H1N1 strain of human influenza and the H9N2 and H5N1 strains of avian influenza.
The theory behind the treatment is that the body can fight off influenza viruses with enhanced immune responses.
"Our study demonstrated that Gamma Delta-T cells found in human blood can prevent influenza viruses from replicating. These cells play an important role in the anti-influenza immune response of our bodies," Said Tu Wenwei of HKU's Department of Paediatrics and Adolescent Medicine.
The study found that Gamma Delta T cells may reduce the chances of an H1N1 infection by a factor of more than 100 and of an H5N1 virus infection by a factor of 1,000.
Unfortunately, human blood contains very few of these cells, which account for between 2 and 10 percent of white blood cells. Phosphoantigen may drastically boost the number of these cells.
"Existing anti-flu drugs mainly work by targeting specific viral proteins and thereby blocking virus replication and spread. However, viruses are able to mutate to escape the action of some of these drugs," said Professor Malik Peiris from the Department of Microbiology of the HKU School of Medicine.
"Many viruses are beginning to develop resistance to many drugs. Most seasonal H1N1 viruses are now resistant to oselatmivir, or tamiflu. Most H3N2 viruses are resistant to drugs amantadine and rimantadine.
Pandemic H1N1 viruses are also resistant to amantadine or rimantadine," he said. "There is an acute need to develop alternative strategies for influenza therapy and this treatment is one possible way."
The researchers believe that enhancing the body's immune response is an alternative strategy that will remain effective regardless of virus mutation.
"Since phosphoantigen has already been approved for human use, the new application of an old drug offers a ready and cost-effective solution to viral infections," said Professor Lau Yu-lung from HKU's Department of Paediatrics and Adolescent Medicine.
However, he warned that research is still at a pre-clinical stage and urged people not to self-medicate phosphoantigen if they experience flu-like symptoms. It will likely take two to three years to fully research the effects of the drug.
(HK Edition 08/15/2009 page1)