White blood cells are important soldiers in the immune system, but their numbers can decrease due to medical conditions or treatments such as chemotherapy. Yale scientists have now discovered a molecule that can be injected to quickly boost the number of white blood cells, helping people fight off infections without the use of antibiotics.
Neutrophils are a type of white blood cell that are the first responders to foreign threats such as bacteria, viruses or fungi. Unfortunately, in the case of neutropenia, the number of neutrophils decreases, which can be the result of certain genetic conditions or a side effect of treatments such as chemotherapy. Either way, a low neutrophil count can make an infection more severe, and there aren't many ways to raise it.
In the new study, Yale scientists discovered a molecule that may help. The molecule, formally known as A485 and informally known as "panerin," blocks certain proteins that regulate gene expression and triggers the release of neutrophils and other white blood cells from the bone marrow.
In tests on mice, A485 was found to work quickly and only temporarily, with white blood cell counts returning to normal after 12 hours. This may sound like a disadvantage, but it's actually a good thing, the team said.
Nikolai Jaschke, lead author of the study, said: "Currently, the main treatment for low white blood cell counts is G-CSF, or granulocyte colony-stimulating factor, which is produced by the body and can be administered as a drug. But its effects last longer and can be harmful in some cases, thus limiting its widespread clinical use. A485 is as effective as G-CSF, but less durable."
The team tested whether an increase in white blood cells could help clear the infection. They gave mice chemotherapy to destroy their bone marrow, which typically lowers their immune response to infection. They then infected the animals with Listeria and injected them with A485. Sure enough, mice treated with this molecule were able to clear the infection more effectively and had higher survival rates than the control group. The results suggest that molecules like A485 could reduce our reliance on antibiotics.
"When patients develop low white blood cell counts after chemotherapy, a condition known as neutropenic fever, antibiotics are the only approved treatment," Jaschke said. "A485 may be another option."
However, there is still much work to be done. Exactly how A485 works remains to be discovered, and it will need to be tested on other, more common infections, the team said.
The study was published in the journal Immunity.