KLRK1 and systemic lupus erythematosus: This is the first study to demonstrate that the abnormally increased NKG2D+CD4+ T cells of SLE can kill NKG2DL+ Tregs, and the findings contrast the previous report of chimeric NKG2D-transduced CD8+ T cells killing NKG2DL+ Treg cells in a murine model of ovarian cancer36.