Chronic Granulomatous Disease (CGD)

Chronic granulomatous disease (CGD) is a rare, inherited disorder that affects the immune system. It is characterized by the inability of phagocytic cells, such as neutrophils and macrophages, to kill certain bacteria and fungi due to a defect in the production of reactive oxygen species (ROS).

Causes and Risk Factors

CGD is caused by mutations in one of four genes that encode subunits of the enzyme NADPH oxidase. This enzyme is essential for the production of ROS, which are necessary for killing ingested microorganisms. The mutations can be inherited in an X-linked or autosomal recessive pattern.

Symptoms

The symptoms of CGD typically appear in early childhood and may include:

• Recurring infections, such as pneumonia, abscesses, and osteomyelitis
• Granulomas, which are areas of inflammation that can form in various parts of the body, including the lungs, liver, and skin
• Lymphadenopathy, or swollen lymph nodes
• Fever and fatigue
• Gastrointestinal problems, such as diarrhea and abdominal pain

Diagnosis

The diagnosis of CGD is typically made through a combination of laboratory tests, including:

• Dihydrorhodamine 123 (DHR) flow cytometry test, which measures the production of ROS in phagocytic cells
• Nitroblue tetrazolium (NBT) test, which also measures the production of ROS
• Genetic testing to identify mutations in the genes that encode NADPH oxidase subunits

Treatment and Management

The treatment and management of CGD typically involve:

• Antibiotic prophylaxis to prevent infections
• Interferon-gamma therapy to enhance the immune response
• Surgical drainage or debridement of abscesses and granulomas
• Hematopoietic stem cell transplantation (HSCT) in severe cases
• Gene therapy, which is still an experimental treatment for CGD

Complications and Prognosis

If left untreated or undertreated, CGD can lead to serious complications, including:

• Recurring and severe infections
• Organ damage, such as lung and liver disease
• Malignancy, such as lymphoma

The prognosis for individuals with CGD has improved significantly with advances in treatment and management. However, the condition still requires careful monitoring and aggressive treatment to prevent complications and improve quality of life.