Defective neutrophil superoxide production in patients with G6PC3 deficiency resulting from homozygous inheritance of G6PC3 G260R. (A) DHR assay. (Left panels) Neutrophils in orange by side scatter (SSC) and forward scatter (FSC) characteristics. Fluorescence of DHR-loaded neutrophils after PMA stimulation for each subject is graphed in the corresponding panels to the right. Prestimulation histograms for each subject showed MFIs less than 200. HD indicates healthy donor; and P1 and P2, affected brother and sister, respectively. The number in the top left corner of each panel on the right indicates the percentage of gated cells that failed to respond to PMA. (B) Real-time assay of superoxide production. PMA was used as the stimulus. Data are from a single experiment with 2 replicates at each time point plotted as a single curve for healthy donors versus patients. (C) Endpoint superoxide production assay. Production of superoxide was measured 15 minutes after the addition of the indicated agonists. Data are shown for a healthy donor versus the average of the 2 patients together. Data are summarized from a single experiment in which each subject was tested in duplicate. (B-C) Data were obtained after the patients were treated for 5 months with G-CSF.