PDCD1 and systemic lupus erythematosus: As shown in Fig. 4, the frequency of TIM-3+PD-1+NK cells was positively correlated with anti-dsDNA (r2 = 0.22, P = 0.013), and the MFI of TIM-3 on TIM-3+PD-1+ NK cells was significantly elevated in anti-RIB-P positive SLE patients (P = 0.05).