A 3-year-old boy,who is small for his age,has a history of pyogenic (pus-producing)infections and cutaneous skin abscesses.Physical examination is remarkable for high fever,enlarged liver and spleen,and swollen cervical lymph nodes.A culture from an abscess on his arm reveals Staphylococcus aureus,a gram-positive bacteria that is also catalase-positive.Immunoglobulin and complement levels are normal.Results of the nitroblue tetrazolium test are consistent with a diagnosis of chronic granulomatous disease (CGD).The boy's immunodeficiency involves impaired generation of which of the following?
A)C5a
B)C-reactive protein
C)Mannose-binding lectin
D)Reactive oxygen intermediates
E)Membrane attack complex

Question

Quizplus · Accepted Answer

Chronic granulomatous disease (CGD)is a rare,inherited immunodeficiency disease associated with a defective intracellular respiratory burst in phagocytes.It consists of a group of heterogeneous disorders of oxidative metabolism in which the pathways required for generation of toxic reactive oxygen species (ROIs)are impaired.In patients with CGD,phagocytosis occurs normally,but the engulfed microbes are not killed and they multiply within the cell.In this way,patients are susceptible to recurrent infections with organisms such as Staphylococcus,which are of low virulence in normal hosts.

A 3-Year-Old Boy,who Is Small for His Age,has a History