A recent finding can be a great help in preventing deaths from severe flu outbreaks.
Specifically, the researchers found that immune cells called "natural killer T cells" may reduce the overwhelming numbers of another type of immune cells called "inflammatory monocytes", which when present in large numbers lead to lung injury at the end stage of severe flu infection.
"We hope this study will ultimately benefit individuals, especially the young, who succumb to a severe form of flu infection," said Ling-Pei Ho, who led the work at the MRC Human Immunology Unit, Oxford University.
"The study highlights a key immune process that occurs in severe flu infection, and provides a platform for a new approach and further research in this area," added Ho, the Journal of Leukocyte Biology reports.
To make their discovery, scientists infected three groups of mice with H1N1 flu virus, according to an Oxford statement.
The first group included normal mice, the second group was devoid of natural killer T cells, and the third group was given a treatment that specifically activated natural killer T cells.
Researchers observed the outcome of flu infection and found that the mice without natural killer T cells did worst, and those with activated killer T cells did best.
Mice that lacked natural killer T cells had increased amounts of monocytes in the lungs, and severe lung injury similar to those seen in Spanish flu and lethal swine flu.
"Despite affecting practically everyone, the flu may be one of the most underestimated viruses in terms of its devastating potential," said John Wherry, deputy editor of the Journal of Leukocyte Biology, which published the study.