ENTPD1 and hepatitis B virus infection: In contrast, the frequency of CD39+FoxP3+ Treg cells was significantly negatively correlated with serum ALT in total hepatitis B patients (n = 39, r = 0.344, P = 0.012), and a strong correlation was also observed in CAH patients (r = 0.508, P = 0.019) (Figure 4B, middle panel).