Significantly higher levels of CLEC18 in circulating T cells (CD3+), monocytes (CD14+), and neutrophils (CD66b+) were observed in rheumatic patients with HCV infection (n = 41, median 19.79, interquartile range [IQR] 11.65–29.68; 50.96, IQR 37.19–78.42; 97.57, IQR 60.25–227.06; respectively) compared with those without infection (n = 45, 12.00, IQR 9.15–19.47, P < 0.05; 36.54, IQR 23.00–47.81, P = 0.001; 46.80, IQR 38.72–82.99, P < 0.001; respectively, Fig. 2a,c and d). Here, CD14 is linked to infection.