Chronic granulomatous disease (CGD)

Definition

Chronic granulomatous disease (CGD) is a rare genetic immunodeficiency disorder where phagocytes, like neutrophils, are unable to effectively kill certain types of bacteria and fungi. This defect arises due to a failure in the respiratory burst, which is crucial for producing reactive oxygen species needed for microbial killing. Patients with CGD often experience recurrent infections and granuloma formation due to the accumulation of immune cells that cannot eliminate the pathogens, leading to chronic inflammation.

5 Must Know Facts For Your Next Test

1. CGD primarily affects males due to its X-linked inheritance pattern, though there are autosomal recessive forms as well.
2. Patients with CGD have an increased susceptibility to infections from catalase-positive organisms such as Staphylococcus aureus and Aspergillus species.
3. Diagnosis of CGD typically involves measuring the oxidative burst activity of phagocytes using flow cytometry or nitroblue tetrazolium (NBT) tests.
4. Treatment often includes prophylactic antibiotics and antifungal medications, along with interferon-gamma therapy to help boost immune response.
5. Bone marrow transplantation can be a curative option for some patients with severe forms of CGD.

Review Questions

• How does the defect in the NADPH oxidase enzyme complex affect the immune response in individuals with chronic granulomatous disease?
  • The defect in the NADPH oxidase enzyme complex prevents phagocytes from generating reactive oxygen species necessary for killing certain pathogens. As a result, individuals with chronic granulomatous disease are unable to effectively eliminate catalase-positive bacteria and fungi. This leads to recurrent infections and chronic inflammation as the body continues to mount an immune response without being able to clear the invading microorganisms.
• What role do granulomas play in chronic granulomatous disease, and how do they contribute to the clinical symptoms experienced by patients?
  • Granulomas form as a response to chronic inflammation and represent an attempt by the immune system to isolate pathogens that cannot be eradicated. In chronic granulomatous disease, the accumulation of these inflammatory cells can lead to tissue damage and organ dysfunction over time. Patients may experience symptoms such as pain, swelling, and functional impairment in affected areas due to the persistent presence of granulomas.
• Evaluate the long-term management strategies for patients with chronic granulomatous disease, considering both prevention of infections and treatment options.
  • Long-term management of chronic granulomatous disease focuses on preventing infections through prophylactic antibiotics and antifungal medications, which are essential given their susceptibility to certain pathogens. Additionally, interferon-gamma therapy may be utilized to enhance the immune response. For severe cases, bone marrow transplantation offers a potential cure by providing patients with healthy donor cells that can produce functional NADPH oxidase. Regular monitoring for infections and complications is crucial to ensure optimal care for these patients.

Related terms

Phagocytes: A type of immune cell that engulfs and destroys pathogens, including bacteria and fungi.

NADPH oxidase: An enzyme complex in phagocytes that generates reactive oxygen species during the respiratory burst, crucial for pathogen elimination.

Granulomas: Small areas of inflammation that form when the immune system attempts to wall off substances it cannot eliminate, often seen in CGD patients.