In addition to confirming the presence of anti-KIR autoantibodies in SLE patients, our data demonstrate that these autoantibodies react with natively folded membrane-bound KIRs expressed on human cells, and that reactivity to KIR2DL2, KIR3DL2, KIR2DS2, KIR2DS4, and KIR2DL4 is also present in SLE patients. This evidence concerns the gene KIR3DL2 and systemic lupus erythematosus.