Updated: Sep 6, 2021
A team of Israeli scientists at Technion-Israel of Technology wanted to know why COVID-19 hit the elderly population so hard, and it turns out that little cells developed in childhood may hold the answer.
According to their study, recently published in the peer-reviewed online medical journal Blood, the answer lies with the "B cells." B lymphocytes are cells produced in the bone marrow, which then produce antibodies to fight off pathogens such as viruses and other diseases.
"When you are young, you have young cells, and young cells have a very diverse ability to recognize anything (pathogenic) that comes into your body," said Professor Doron Melamed at Technion. Melamed and doctoral student Reem Dowery led the team looking into why the elderly were more susceptible to severe cases of COVID and why vaccines seemed to wane and not be as effective in the older population.
When an invading germ is detected, B cells are called up for "active duty" from the bone marrow. Once the job is done, they don't just disappear, however. Instead, they go into a "reservist status" or turn into "memory" B cells and wait in the bone marrow until they are needed again. Once the immune system learns how to fight a disease, future responses are so swift that a person might not even know he has been exposed to the pathogen.
Fending off new illnesses gets tricky for the elderly because the body is designed to keep things in balance or in a state of homeostasis. And while B cells in the blood system (the ones that actively fend off invaders) are short-lived, the "memory" B cells are long-lived. So, the longer you live, the more bugs you fight off and the more "memory" B cells you have in storage.
Unfortunately, this means there is less room in the bloodstream for new or young B cells that would be ready to tackle a new foe such as coronavirus.
Melamed and his research team started looking for a way to clear out some of the "storage" B cells and thus make room for new B cells again.
"We found specific hormonal signals produced by the old B cells, the "memory" cells, that inhibit the bone marrow from producing new B cells. This is a huge discovery. It is like finding a needle in a haystack," Melamed said.
The team hopes to find specific drugs or other treatments that can cause this immune system rejuvenation. Meanwhile, Melamed recommends frequent booster vaccines for the elderly and possibly giving them inoculations from different manufacturers.