KLRD1 and systemic lupus erythematosus: Recently, we demonstrated that a subset (3.4%) of SLE patients harbors functional autoantibodies to the CD94/NKG2A and CD94/NKG2C receptors, which interfere with HLA class I-mediated regulation of NK cell cytotoxicity resulting in a dysregulation of the discrimination between self and non-self-cells (19, 20).