In addition to PD-1+ CD4 αβ T cells, the percentages of PD-1+ effector CD8 αβ T cells and PD-1+ immediately activated CD8 αβ T cells were higher in the patients with SLE than those in the HCs (all p<0.05; figure 2A). This evidence concerns the gene PDCD1 and systemic lupus erythematosus.