Chronic Granulomatous Disease

Indications for Testing

Severe and recurrent bacterial and fungal (yeast/mold) infections, presence of granulomas, colitis, pneumonias, osteomyelitis, lymphadenitis

Laboratory Testing

Neutrophil oxidative burst assay (DHR) via flow cytometry – preferred test; disease indicated by absence or significant alteration of activity
Other, less-reliable tests – measurement of superoxide production, ferrocytochrome reduction, nitroblue tetrazolium test
Nonspecific testing to rule out other disorders
- Serum quantitative immunoglobulins – rule out hypogammaglobulinemia
- Complement activity enzyme immunoassay – rule out complement deficiency
- CBC with differential – rule out other causes of chronic infection (neutropenic disorders)
- Leukocyte adhesion deficiency panel – rule out leukocyte adhesion deficiency
Genetic testing
- Molecular methods (PCR) to identify mutations via high-resolution melting analysis offered on a research basis
  - Contact appropriate medical director/laboratory

Differential Diagnosis

Chronic recurrent infections
- Hypogammaglobulinemia
- Complement deficiency
- Leukocyte adhesion deficiency type 1
- Hyper IgE syndrome (Job syndrome)
- Kostmann agranulocytosis
- Autoimmune neutropenia
- Myeloperoxidase deficiency
- Innate immune deficiency
- Wiskott-Aldrich syndrome
- Severe combined immunodeficiency
- HIV/AIDS
Bowel disease
- IBD
- Celiac disease
Granulomatous disease
- Sarcoidosis
- Infection
  - Mycobacterium tuberculosis

Chronic granulomatous disease (CGD) is a leukocyte function defect where phagocytic cells ingest but do not digest bacteria due to a malfunction of the nicotinamide adenosine dinucleotide phosphate (NADPH) oxidase system. CGD is characterized by severe, recurring infections with granuloma formation.

Epidemiology

Incidence – 1/250,000 births
Age – mean diagnosis from birth to 65 years
Sex – M>F by 85%

Inheritance

X-linked form – 60-70%
- Involves mutations in the 13 exons encoding the 91-kD heavy chain of cytochrome b558 in the CYBB gene
  - Typically earlier onset and more severe disease than autosomal recessive CGD
Autosomal recessive forms
- Most common form (NCF1 gene)(20-25%) involves mutations in the 47-kD cytosolic oxidase component on chromosome 7
- Two other autosomal recessive forms (5-10%) involve the 67-kD cytosolic factor encoded on chromosome 1 and the 22-kD light chain of cytochrome b558 in the CYBA gene

Pathophysiology

Function of neutrophils
- First line of defense against bacterial and fungal infections
- Migrate to the site of infection – phagocytosis occurs, which generates microbicidal reactive oxygen products
- Neutrophil granules fuse to the phagosome
- Other nonoxidative factors are added that assist in killing microorganisms
CGD – result of abnormalities of neutrophils and macrophages
- Cause defective microbicidal oxidant production secondary to a defect in the neutrophil respiratory burst
- Result in decreased production of superoxide, hydrogen peroxide, hydroxyl radical, and hypochlorite ion within neutrophil and macrophages
- Defect causes susceptibility to infections from organisms that may be nonpathogenic in an immunocompetent individual
  - Most common infections – bacterial produced by catalase-positive microorganisms and fungal organisms (yeasts, molds)
Genetic mutations within the CYBB or CYBA genes – result in a malfunction of one of the phagocyte NADPH oxidase components

Clinical Presentation

Signs and symptoms usually appear very early in childhood
- May not present until later in life, especially with mild cases or autosomal recessive/variant forms of X-linked CGD
Gastrointestinal – nausea, diarrhea, vomiting, colitis with inflammatory bowel disease (IBD)-like manifestations (blood in stool, granuloma in GI tract)
Genitourinary – urethral strictures, bladder granulomas
Pulmonary – encapsulated pneumonias
Skin and musculoskeletal – lymphadenitis, skin and visceral abscesses, osteomyelitis
Infections
- Eventual chronic obstructive granulomas form at sites of infection
- Characterized by bacterial and fungal infections

Treatment

Early diagnosis and aggressive therapy, including use of interferon gamma and fungal and bacterial prophylaxis, markedly improves prognosis
Recent studies indicate successful results in transplanted patients with gene therapy as a future possibility
- Bone marrow and stem cell transplant may be curative

Tests generally appear in the order most useful for common clinical situations

Test name: Neutrophil Oxidative Burst Assay (DHR)

ARUP #: 0096657

Methodology: Semi-Quantitative Flow Cytometry

Use:

Use along with other clinical findings to diagnose CGD

Characterize autosomal recessive CGD and X-linked carrier status

Limitations:

Results alone not diagnostic

Live neutrophils required

Sample must remain ambient and be tested within 48 hours of collection

Follow-up:

For abnormal results, consult with laboratory medical director

Test name: Immunoglobulins (IgA, IgG, IgM), Quantitative

ARUP #: 0050630

Methodology: Quantitative Nephelometry

Use:

Initial test in workup of immunoglobulin disorders

In adults and older children with suspected hypogammaglobulinemia, order in conjunction with serum protein electrophoresis and immunofixation

Panel includes IgA, IgG, IgM

Test name: Complement Activity Enzyme Immunoassay, Total

ARUP #: 0050198

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Use:

Rule out complement deficiency

Test name: CBC with Platelet Count and Automated Differential

ARUP #: 0040003

Methodology: Automated Cell Count/Differential

Use:

Rule out other causes of chronic infection, including anemia

Test name: Chronic Granulomatous Disease (CYBB Gene Scanning and NCF1 Exon 2 GT Deletion) with Reflex to CYBB Sequencing

ARUP #: 2006356

Methodology: High Resolution Melt Analysis

Use:

Confirm diagnosis of CGD

Carrier screening for individuals with family history of CGD when specific familial mutation is not known

Limitations:

Lack of detectable mutation does not rule out CGD

Test name: Familial Mutation, Targeted Sequencing

ARUP #: 2001961

Methodology: Polymerase Chain Reaction/Sequencing

Use:

Molecular PCR/sequencing test to detect previously characterized mutation in a family member

Documentation of the familial gene mutation(s) is required to perform targeted sequencing

Consultation with a genetics counselor is advised

Additional Tests Available

Test name: Chronic Granulomatous Disease (NCF1) Exon 2 GT Deletion

ARUP #: 2006366

Methodology: High Resolution Melt Analysis

Comments:

Confirm diagnosis of autosomal recessive CGD

Test name: Chronic Granulomatous Disease, X-Linked (CYBB) Gene Scanning with Reflex to Sequencing

ARUP #: 2006361

Methodology: High Resolution Melt Analysis

Comments:

Confirm diagnosis of X-linked CGD

Test name: Leukocyte Adhesion Deficiency Panel

ARUP #: 2004359

Methodology: Semi-Quantitative Flow Cytometry

Comments:

Rule out leukocyte adhesion deficiency

Panel measures CD11b, CD15, and CD18 on neutrophils

General

ARUP Institute for Clinical and Experimental Pathology®

Comprehensive Review: June 2012
Last Update: March 2013

Bruton Agammaglobulinemia

Common Variable Immune Deficiency

Complement Deficiency

Human Immunodeficiency Virus

Immunodeficiency, Innate System

Immunoglobulin Disorders

Leukocyte Adhesion Deficiency

Neutrophil Disorders

Sarcoidosis

Severe Combined Immunodeficiencies

T-Cell Deficiency Disorders, Inherited