KIR3DL1 and acute myeloid leukemia: KIR3DL1*004 is also reported to be protective against relapse in patients with acute myeloid leukemia (AML) after HLA-matched HSCT [15] and against HIV disease progression [30], which emphasizes the underlying and intriguing function of this frequent null KIR3DL1 allele in Caucasians.