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Key Features

Essentials of Diagnosis

  • Frequent sinopulmonary infections secondary to humoral immune deficiency

  • Low serum immunoglobulin levels and deficient functional antibody responses

  • Primary defect may be with B cells or T cells

General Considerations

  • Most common symptomatic primary immunodeficiency disorder

  • Heterogeneous immunodeficiency disorder clinically characterized by an increased incidence of recurrent infections, autoimmune phenomena, and neoplastic diseases

Demographics

  • Onset is generally in early adulthood but it can occur at any age

  • The prevalence is about 1 in 25,000 in the United States

  • Most cases are sporadic; about 10–20% are familial

Clinical Findings

  • Increased susceptibility to infections, especially with encapsulated organisms

  • Recurrent sinusitis

  • Bronchitis

  • Otitis

  • Pharyngitis

  • Pneumonia

  • Gastrointestinal infections and dysfunction

  • Autoimmune cytopenias

  • Autoimmune endocrinopathies, seronegative rheumatic disease, and gastrointestinal disorders

  • Lymph nodes may be enlarged in these patients, yet biopsies show marked reduction in plasma cells

Diagnosis

  • Assess serum quantitative immunoglobulin levels

  • Reduced serum levels of IgG, IgM, or IgA

  • Diagnosis is made in patients who have reduced serum immunoglobulins and poor antibody response to vaccines, after exclusion of secondary causes, such as

    • Proteinuria

    • Protein-losing enteropathy

    • Drug effects (eg, rituximab, antiepileptics)

    • Chronic lymphocytic leukemia, lymphoma, and plasma cell myeloma

Treatment

  • Should be treated aggressively with antibiotics at the first sign of infection; antibiotic therapy should cover encapsulated bacteria

  • Infections with other microorganisms also can develop, including viruses, parasites, and extracellular gram-positive or gram-negative bacteria (such as Staphylococcus aureus or Pseudomonas aeruginosa)

Outcome

Complications

  • Infections may be prolonged or associated with unusual complications such as meningitis or sepsis

Prevention

  • Mainstay of preventive therapy

    • Subcutaneous or intravenous immunoglobulin replacement therapy, typically provided every 1–4 weeks, with a typical monthly dose of 300–600 mg/kg

    • Adjustment of the dosage or infusion interval is made primarily on the basis of clinical responses, in addition to serum IgG levels

    • Such therapy is essential for decreasing the incidence of potentially life-threatening infections, increasing quality of life, and reducing the progression of lung disease

When to Refer

  • Refer patients with low serum immunoglobulins and history of recurrent or unusual infections, autoimmune disease, or family history of immunodeficiency

  • The presence of bronchiectasis without a known underlying cause such as cystic fibrosis should raise the suspicion of a primary immunodeficiency; even when serum immunoglobulins are normal, the patient can have a specific antibody deficiency that would warrant further evaluation

References

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Bonilla  FA  et al. Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma & Immunology; the American College of Allergy, Asthma ...

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