Considering the immunosuppressive role of TIM-3 and PD-1 in SLE, the fact that co-expression of PD-1 and TIM-3 on cells is correlated with disease clinical outcomes and that the cells co-expressing these proteins were dysfunctional, it was hypothesized that the co-expression of these two markers on NK cells may be associated with SLE and its clinical severity. Here, PDCD1 is linked to systemic lupus erythematosus.