MDSC: Markers, development, states, and unaddressed complexity

Myeloid-derived suppressor cells (MDSCs) are one of the most discussed biological entities in immunology. While the context and classification of this group of cells has evolved, MDSCs most commonly describe cells arising during chronic inflammation, especially late-stage cancers, and are defined by their T cell immunosuppressive functions. This MDSC concept has helped explain myeloid phenomena associated with disease outcome, but currently lacks clear definitions and a unifying framework across pathologies. Here, we propose such a framework to classify MDSCs as discrete cell states based on activation signals in myeloid populations leading to suppressive modes characterized by specific, measurable effects. Developing this level of knowledge of myeloid states across pathological conditions may ultimately transform how disparate diseases are grouped and treated.

Automated summary

MDSCs are a widely discussed biological entity in immunology, commonly describing cells that arise during chronic inflammation with T cell immunosuppressive functions. Currently lacking clear definitions and a unifying framework across pathologies, we propose a framework based on activation signals to classify MDSCs as discrete cell states. Developing this knowledge of myeloid states across pathological conditions may transform how diseases are grouped and treated.