In fact, we have also observed dramatic increase in ICAM-1 (Figures 7A and 7B) and ICOS (Figures 7C and 7D) expressions on peripheral CD4+ T cells from moderate/severe SLE patients when compared to HCs and mild SLE, which indicated the hyper-activation of CD4+ T cells in moderate/severe SLE. Here, ICOS is linked to systemic lupus erythematosus.