In addition, to verify whether T cell exhaustion in PTC arise from HT, we analyzed the expression of immune cells and PD-1 in NG&HT and PTC&HT, and found that the expression of B cells, CD3+PD-1+, CD3+CD4+PD-1+ and CD3+CD8+PD-1+ in PTC&HT was significantly higher than that in NG&HT group. Here, CD4 is linked to hematocrit.