Recent research has further revealed that lupus B cells with enhanced PD-1 expression exhibit functionally reduced proliferation along with reduced PD-L1 up-regulation capacity upon stimulation by interleukin-2(IL-2)/IL-10, anti-B cell receptor (anti-BCR), CpG, and CD40L [164]. The gene discussed is PDCD1; the disease is systemic lupus erythematosus.