Identification of a rare FcγRIIIB-null donor lacking FCGR3B gene and protein. (A) Genomic PCR was performed on DNA from 25 healthy donors, using primers specific for the HNA1a (NA1) and HNA1b (NA2) allotypes. Jak2 gene was amplified as control. (B) Whole blood from FcγRIIIB WT donors and the FcγRIIIB-null donor was stained with FITC-labeled anti-CD16, anti-CD32, and anti-CD64 antibodies and selected populations, based on scatter properties corresponding to granulocyte and lymphocytes, analyzed by flow cytometry. The data shown are representative of ≥3 experiments.