Osteoporosis could hold key to fighting influenza

According to research recently published in the Journal of Experimental Medicine, an osteoporosis drug may be effective in killing a range of influenza viruses, including those like the H5N1 bird flu virus that is dangerous to people.

The drug, pamidronate, boosts a certain class of human immune cells and initiates a killing spree to exterminate host cells infected with flu viruses. This is different from antiviral drugs that target and mute flu viruses, Reuters Health reports.

The researchers studied mice that were given a human immune system. The class of human immune cells, called gamma-delta T-cells, recognized host cells infected with flu viruses, punched holes through the membrane of the infected cells and then injected an enzyme into the cells, killing them.

"The drug activates and expands this group of T-cells, their numbers dramatically increase and they kill these virus-infected cells by secreting and injecting an enzyme," Professor Malik Peiris, a member of the research team and a leading microbiologist at the University of Hong Kong, said, according to Reuters Health.

The drug does not deal directly with flu viruses and, as a result, it may be unlikely to become useless as a result of mutating and resistant viruses.

"This drug boosts our own immune system, so the likelihood of it triggering a mutation (that results in viruses becoming resistant) is lower," Professor Lau Yu-lung, head of pediatrics and adolescent medicine at the same university, said, according to Reuters Health.

The mice were infected separately with the pandemic H1N1 swine flu virus, H5N1 and H9N2 bird flu viruses. Those treated with the drug recovered very quickly while those without treatment died within a few days. The drug only worked on “humanized mice” that had the gamma-delta T-cells to begin with, demonstrating that the drug only boosts the numbers of these cells, but does not create them.

The scientists are preparing to test the efficacy of pamidronate in human clinical trials.