For instance, ankylosing spondylitis is one of these rheumatic diseases in which the frequency of two KIR genes (KIR2DL3 and KIR2DL5) and two HLA ligands (HLA-B27 and HLA-C2Lys80) was significantly different between AS patients and healthy controls [41]. This evidence concerns the gene KIR2DL3 and ankylosing spondylitis.