Some viruses can be dormant throughout a person’s life and cause no harm but become dangerous when the immune system is weakened. One of such viruses is human cytomegalovirus (CMV). Harmless to the general public but life-threatening to patients with a supressed immune system.
The Unusual Approach: Boosting Immune System
Teaming up with Dr. Marc Dalod, an expert on CMV immunity, the researchers led by Prof. Sieweke took an unusual approach. Instead of targeting the virus with antiviral treatments, they focused on strengthening the immune system to fight the virus on its own.
Cytokine: Small but Mighty Molecule
The new approach focuses on the cytokine known as macrophage colony-stimulating factor (M-CSF, CSF1). It’s a small signaling molecule that works as a messenger and activator for the immune system. “The cytokine boosts the production of specific white blood cells, mainly monocytes and macrophages,” says Dr. Prashanth Kumar Kandalla, one of the leading authors of the study.
Although normally monocytes and macrophages were not known as the primary defense force against viruses, the authors found that they activated other immune cells, so-called natural killer cells, that help fight the virus. “In case of immunocompromised patients, the number of white blood cells is very low. This is why their body is defenseless against infections. M-CSF treatment would boost the immune system by triggering the production of new white blood cells and restore the patient’s ability to fight the pathogen,” explains Dr. Kandalla.
The team could show that M-CSF boosted production of white blood cells in immunocompromised mice and in such a way protected them from an otherwise lethal CMV infection without affecting bone marrow transplantation.
Clinical Trials Are Needed
The study showed that the concept worked in mice and in human cells in a culture dish. “We are keen to expand our findings and support them with data derived from patients in the clinic. For example, we would like to test our cytokine approach as a prophylactic intervention following bone marrow transplantation to prevent CMV reactivation. For this, clinical trials are necessary. We are now looking for partners who could help us finance such trials,” concludes Prof. Sieweke.
Because of its unique ability to boost the immune defence, the new approach is not limited to CMV or bone marrow transplantation patients. The authors expect that it could also be useful to treat other viral infections, and help other patients with a weakened immune system, for example after sepsis or chemotherapy.