KLRC4 and Behcet disease: In addition, many other susceptibility loci for BD development are also located in genes related to the innate immune system, including C–C motif chemokine receptor (CCR)1-CCR3, killer cell lectin-like receptor C4 (KLRC4), IL1B, interferon regulatory factor (IRF)8 and interferon gamma receptor 1 (IFNGR1) (5, 10, 11).