Primary phagocytic defects must be included in the differential diagnosis of recurrent infection and fever in a child and occasionally in an adult. Early diagnosis is essential, because manifestations of infection are usually blunted and rapid intervention can be lifesaving. In general, patients are identified at a young age on the basis of their susceptibility to normally nonpathogenic bacteria or fungi. In some cases, the infectious agents point to the disorder (Table 1): catalase-positive microorganisms and aspergillosis species are characteristic of chronic granulomatous disease,¹ and atypical mycobacteria suggest a defect in the interferon-γ–interleukin-12 axis.² These bacterial infections contrast with the . . .