Macrophage colony-stimulating factor as a weapon against cytomegalovirus.

Cytomegalovirus (CMV) infection is one of the severe opportunistic infections faced by severely immunocompromised patients. High viral loads cause tissue-invasive disease and expose to death or various indirect effects. Substantial progress was made in monitoring active infection, and antiviral drugs were developed. However, dose-limiting toxicities and genotypic resistance limit therapeutic efficacy and vaccine development is hampered by the complex biology of the virus. In this issue of EMBO Molecular Medicine, Kandalla et al (2023) suggest an innovative strategy using the cytokine macrophage colony-stimulating factor (M-CSF) whose clinical development was left behind two decades ago. By stimulating an endogenous immune defense mechanism, M-CSF promotes viral clearance in a mouse model of hematopoietic stem cell transplantation, without impairing stem cell engraftment. These results reactivate the interest in the potential therapeutic use of this cytokine.