RNA extraction and quantitative real time polymerase chain reaction (qRT-PCR)
Total RNA was extracted from peripheral blood, fresh-frozen biopsies and pWSLV-02-LILRA3 plasmid- or pWSLV-02-transfected U937 cells using the Trizol reagent (Invitrogen, Carlsbad, USA). The quantity and quality of the RNA samples were assessed using a NanoDrop2000 spectrophotometer (Thermo Scientific, Waltham, USA). Total RNA (1 μg) was used to synthesize cDNA using a first-strand cDNA synthesis kit (Thermo Scientific, Waltham, USA). qRT-PCR was subsequently performed using the QuantStudioTM6 Flex Real-Time PCR instrument (ABI, Carlsbad, USA) with the SYBR® Premix Ex TaqTM II mix (Takara, Kusatsu, Japan). The 2−ΔΔCT method was applied to determine the relative mRNA levels normalized to the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH).