ICOS and systemic lupus erythematosus: The results showed that the frequencies of effector cTfh including PD1+cTfh, PD1+cTfh1, PD1+cTfh2, PD1+cTfh17, PD1+ICOS+cTfh, and PD1+ICOS+cTfh1 cells were increased, and the plasmablasts and several associated cytokines were significantly different between active and inactive SLE patients.