Tuberculosis is easily one of the deadliest diseases in the world. The World Health Organization reveals that TB positions itself easily in the top 10 deadliest diseases. Other grim statistics show that about 1.5 million people across the world lose the battle with tuberculosis each year.
Researchers had been wondering how TB became so deadly, and they started by tracing the evolution of a gene variant that can make people more susceptible to the disease. Sciencemag.org wrote an article on the subject of TB reshaping our immune systems.
TB reshaped the immune systems of Europeans from the Iron Age
The Iron Age lasted from 500 BC until 332 BC, which confirms that tuberculosis has been affecting humanity for a pretty long time. But still, the earliest proof of the disease goes even a lot farther, from skeletons buried 9,000 years ago. As for the variant that kills humans today, namely Mycobacterium tuberculosis, it emerged about 2000 years ago.
Lluis Quintana-Murci, who is a population geneticist from the Pasteur Institute and the College of France, declared:
We are [all] the descendants of people who survived past epidemics.
Gaspard Kerner, who’s a graduate student from the University of Paris, discovered something remarkable. He found out that people who inherit two copies of the P1104A variant of the immune gene known as TKY2 are at higher risk of developing severe illness when they get infected with TB.
According to Sebastien Gagneux, who’s a microbiologist at the Swiss Tropical and Public Health Institute, even with new databases like additional ancient DNA samples worldwide and others, it might be just the beginning of studies trying to figure out how our immune systems coevolved with a specific pathogen.
While only a small portion of the people infected with TB will develop an illness with the disease, a major role will be played by how strong the immune system of each person is.