Review Question - QID 100474

Patients with chronic granulomatous disease, in which neutrophils are dysfunctional, have increased susceptibility to infection by catalase-producing organisms.

Chronic granulomatous disease (CGD) is characterized by a deficiency of neutrophil NADPH oxidase. Normally, NADPH oxidase generates reactive oxygen species in the neutrophil which are converted into the antibacterial hydrogen peroxide. Individuals whose neutrophils cannot produce their own hydrogen peroxide are thus highly susceptible to bacteria that break down hydrogen peroxide (catalase-positive organisms). Examples of catalase positive organisms include S. aureus, E. coli, Pseudomonas, and Aspergillus.

Cooper et al. review primary immunodeficiencies. They suggest that if a pattern of unusual or resistant infections is noted and family history is positive for immunodeficiency, the first step in evaluation would be to order a CBC with manual differential as well as immunoglobulin levels. Clinicians must bear in mind that HIV, allergies, structural abnormalities or cystic fibrosis might mimic presentation of immunodeficiencies.

Song et al. review CGD in further detail, noting that CGD is the most common phagocyte-related immunodeficiency. In addition to recurrent bacterial infection, fungal infections and tissue granulomas are common presenting symptoms. Treatment of infections associated with CGD requires long-term antibiotic treatment.

Illustration A is a flowchart showing the steps of diagnosis for a suspected primary immunodeficiency.

Incorrect answers:
Answer 1: Bruton's agammaglobulinemia is characterized by a problem with B cells and immunoglobulin production.
Answer 2: HIV infection affects T cells.
Answer 3: Natural killer cells are part of the innate immune system.
Answer 5: Eosinophils are associated with allergic phenomena and parasitic infection.