Highly purified PMNs express FCGR3A messenger RNA. PMNs from 6 FcγRIIIB WT donors (WT1-6), as well as the FcγRIIIB-null donor (Null), were purified to >99%. Peripheral blood MNCs or CD14⁺ purified monocytes (Mono) were used as controls. RNA was extracted, and RT-PCR was performed using FCGR3A- or FCGR3B-specific primers, corresponding to exon 5 (A) or exon 3 to 4 (B) sequences. PCR products were cut with TaqI restriction enzyme to distinguish the 2 genes and run on a 4% agarose gel. The expected products for FCGR3A or FCGR3B are shown on the right.