Association of killer-cell immunoglobulin-like receptor genes with acute myelogenous leukaemia

Killer-cell immunoglobulin-like receptors (KIRs) are important because of their key roles in NK cell development and function. Some KIR genes have been associated with the incidence of haematological malignancies. This study was designed to determine whether the inheritance of specific KIR genes is associated with susceptibility to acute myelogenous leukaemia (AML) in Persians living in south-western Iran. KIR genes and KIR2DS4 variants were typed by polymerase chain reaction-sequence-specific primer (PCR-SSP) in 167 patients with AML and 169 healthy controls. Our results showed 10% of patients-mostly females-were classified as M3. Flt3 mutations were detected in 26% of patients, most of whom had internal tandem duplication (ITD). The frequency of activating KIRs (aKIRs)-mainly KIR3DS1-was higher in patients, whereas inhibitory KIRs (iKIRs)-particularly KIR3DL1 and KIR2DL1-were more common among controls. The incidence of the KIR2DS4fl allele was higher among patients with non-M3 AML than controls. We also found a higher frequency of 4 or more iKIR genes in the controls and a higher frequency of 4 or more aKIR genes in the patients. Individuals with more iKIR than aKIR belonged predominantly to the control group. Individuals with the telomeric AA genotype who had inherited the KIR2DS4fl allele were more frequent in the patient group. According to our results, increased frequency of aKIRs in patients with AML may lead to the hyperactivation of NK cells against malignant cells with reduced or lack of HLA class I molecules followed by NK cell exhaustion which allow malignant cells to progress.