Both in COVID19 and AOSD patients, we observed that adding PD1 in monocyte cultures, stimulated with M-CSF plus IFN-gamma plus LPS (to induce M1 polarization) or alternatively M-CSF plus IL-4 (to induce M2 polarization), a significant increase of CD206, a M2 macrophage marker whose expression is related to a downregulation of inflammatory processes (37, 38), was observed when compared to PD1 untreated condition. This evidence concerns the gene MRC1 and adult-onset Still disease.