KIRs are expressed on many NK cells and on subpopulations ofT-cells [7], and have been implicated in autoimmuneconditions such as rheumatoid arthritis (RA) [8, 9] and scleroderma [10], where associations have been found with3-domain KIRs (KIR2DL1, 2, and 3) known to recognize HLA-Calleles [11, 12]. This evidence concerns the gene KIR2DL1 and rheumatoid arthritis.