From the Guidelines
Elevated IgE levels are a strong indicator of allergic bronchopulmonary aspergillosis (ABPA), particularly when combined with other diagnostic criteria such as Aspergillus-specific IgE sensitization and clinical deterioration. According to the British Thoracic Society guideline for bronchiectasis in adults 1, elevated total IgE levels are a key component of the diagnostic criteria for ABPA. The guideline suggests that a total serum IgE level >500 IU/mL (or kU/L) is indicative of ABPA, although the precise cut-off is not known.
Key Points to Consider
- Elevated IgE levels can also be associated with other allergic or hypersensitivity responses, such as allergic rhinitis, asthma, atopic dermatitis, food allergies, and parasitic infections.
- The diagnosis of ABPA should be based on a combination of clinical, radiological, and immunological criteria, including Aspergillus-specific IgE sensitization, elevated total IgE levels, and clinical deterioration.
- The presence of high attenuation mucus on CT scan may be useful in diagnosis and in staging the severity of ABPA 1.
- Treatment of ABPA typically involves oral corticosteroids, and the total IgE concentration declines significantly with remission of ABPA on oral corticosteroids 1.
Diagnostic Approach
- The diagnostic approach to ABPA should include testing for Aspergillus-specific IgE and total IgE, as well as clinical evaluation and radiological assessment.
- A combination of testing for Aspergillus-specific IgE and total IgE has been proposed as the most sensitive way to screen for ABPA in patients with asthma, with secondary more specific tests to confirm the diagnosis 1.
- The use of blood tests for Aspergillus-specific IgE and total IgE has the advantage that patients on anti-histamines do not need to stop treatment, and quality data on laboratory performance is more widely available than on skin testing 1.
From the FDA Drug Label
Elevated serum total IgE levels may persist for up to 1 year following discontinuation of XOLAIR. Serum total IgE levels (i.e., bound and unbound) increased after the first dose due to the formation of omalizumab:IgE complexes, which have a slower elimination rate compared with free IgE.
An elevated IgE level may indicate an allergic reaction or inflammation. However, in the context of omalizumab treatment, it may also be due to the formation of omalizumab-IgE complexes, which have a slower elimination rate compared to free IgE. It is essential to consider the clinical context and timing of the measurement when interpreting elevated IgE levels in patients treated with omalizumab 2.
From the Research
Elevated IgE Level Indications
Elevated IgE levels can indicate various conditions, including:
- Allergies, such as allergic rhinitis, asthma, and anaphylaxis 3, 4, 5
- Parasitic infections 6, 7
- Immune dysregulation, including hyper-IgE syndromes (HIES) 6, 7
- Malignancy 6, 7
- Atopic diseases, such as eczema 7
Hyper-IgE Syndromes
Hyper-IgE syndromes are rare primary immunodeficiency diseases characterized by:
- Elevated serum IgE levels
- Recurrent skin abscesses
- Pneumonias leading to pneumatocele formation 7
- Eczema and recurrent infections 6
Diagnosis and Testing
Diagnosis of elevated IgE levels and related conditions involves: