FCN1 (ficolin-1) is a pattern recognition molecule with enriched expression in monocytes broadly. S100A8 and S100A9 (calprotectin subunits) show highly enriched expression in this specific subset, marking an inflammatory monocyte state associated with innate immune activation. Together these markers identify a transcriptionally distinct CD14⁺S100A8/9⁺ monocyte population and distinguish them from classical and non-classical monocyte subsets.
