Develop and apply an assay for evaluating hydrogen peroxide production by human neutrophils following stimulation using flow cytometry. Apply this technique to patients with CGD and the X-linked obligate carriers. The assay has been optimized to improve the detection sensitivity and can reliably detect at the .05% level. This is being applied to the evaluation of CGD patients following allogenic granulocyte transfusions and in CGD patients participating in gene therapy trials.