CD274 and systemic lupus erythematosus: After treatment, the disease activity of the four patients were tended to stable and percentages of PD-L1+ monocytes, PD-1+ CD4 T and CD8 T cells in patients with SLE exhibited positively and negatively correlation with the SLEDAI-2K (Systemic Lupus Erythematosus Disease Activity Index 2000) score, which might associate with the remission of SLE.