Significantly higher levels of plasma M-CSF were detected in AOSD patients (median 9.31 pg/mL, inter-quartile range (IQR) 6.21-16.91 pg/mL) compared with the healthy controls (n = 68) (median 5.31 pg/mL, IQR 4.12-6.85 pg/mL) (nonparametric Mann-Whitney U test, P < 0.0001) (Figure 3(a)). This evidence concerns the gene CSF1 and adult-onset Still disease.