A group of researchers who has been dubbed the “Bat Pack” has dedicated long hours exploring exactly why bats live so long. For the purposes of their experiment, they used one megabat species, the black flying fox bat, and one microbat species, the David’s myotis, and conducted an analysis on the bats’ genes.
The results of a gene analysis stunned the Bat Pack. It revealed that bats’ immune systems work like no other mammal’s in the world. Because of an AWOL gene sequence, the immune system of bats never experiences a cytokine storm, a potentially fatal condition that affects other mammals, including humans.
When attacked by a virus, the immune system produces compounds called cytokines. These are good things. In a perfect situation, the freshly produced cytokines help the body fight the infection.
The best way to explain cytokines is that they operate as couriers, transferring messages from one group of cells to another. Their purpose is to help any area of the body that’s fighting a virus respond in the best possible fashion, preventing the infection or disease from growing even worse, or moving to another part of the body, such as from the stomach to the intestines or from the lungs to the heart.
Cytokines also play an important role in controlling inflammation and are a key component in managing arthritis pain.
But sometimes things go tragically wrong and a cytokine storm rips through the body. When this happens, cytokine production has gone into overdrive, and instead of helping cure the infection, the cytokines cause the various systems to overreact, often with fatal consequences.
The inflammation caused by the presence of the cytokines uses systemic circulation to spread from the localized site where the infection exists and takes over the body. This leads to an increase in extravascular pressure while the body’s tissue perfusion decreases. When the process works properly, the inflammation triggered by the cytokines aids in healing the tissue, but during a cytokine storm, the organs can’t cope with the inflammation and start malfunctioning.
An example of a cytokine storm is seen in someone who is fighting a lung infection. When the immune system responds correctly, the cytokines help the various tissues respond to the infection and fight it off. However, if a cytokine storm takes place, the compounds tell the tissues to overrespond, which leads to the air passageways swelling shut, and causes the person to develop a condition called acute respiratory distress syndrome (ARDS) and go into multisystem organ failure. If the individual doesn’t seek medical care right away, they’ll die.
This is a relatively new area of study. Prior to the early 1990’s, few people had any idea that the immune system could attack itself and turn even more deadly than the original infection.
Armed with this new knowledge of how the human immune system works, historians and medical experts reviewed famous events, such as the 1918 Spanish Flu. The illness started in Europe and quickly became a global problem. Between 1918 and 1919, the virus infected more than 500 million people and claimed between 20 million to 50 million lives. Many victims died within days of developing the first symptom, some only lived a few hours. After investigating the historical files, it’s now believed that cytokine storms were responsible for most of the deaths.
Approximately half of the patients who contracted the avian flu and received medical care died because of cytokine storms.
A missing genome sequence prevents bats from developing cytokine storms, provided they’re not hibernating. Many members of the medical community hope the continued exploration of bat genes and immune systems will uncover ways that the medical community can prevent humans from perishing because of cytokine storms.