PGP and systemic lupus erythematosus: The flow cytometry results showed that, compared with the SR control group and SR with high-dose MP group, the expression of P-gp was downregulated and the accumulation of rhodamine-123 in splenic lymphocytes was increased in the high-dose PNS and TQR groups; therefore, PNS had a significant ability to reverse SR in lupus mice (Fig. 1A,B).