FMO5 and chronic granulomatous disease: To definitively determine the relative contribution of NADPH oxidase versus neutrophil serine proteases against specific pathogens, we evaluated susceptibility of mice with engineered disruptions of these pathways when challenged with a clinical isolate of Aspergillus fumigatus or Burkholderia cepacia, two major pathogens encountered in CGD patients [19], [20], [21], [22], [23].