In addition, we examined whether TNF-α or IL-1β could affect MDL-1 expression; our results showed that TNF-α stimulation of PBMCs from RA patients induced a higher increment of MDL-1-expressing monocytes (median 14.1%, interquartile range [IQR] 13.2–19.1%) compared with stimulation of PBMCs from OA patients (median 3.9%, IQR3.2–4.4%, p<0.01) or healthy controls (median 2.9%, IQR2.7–3.7%, p<0.01; Figure 1E). Here, IL1B is linked to rheumatoid arthritis.