ASPERGILLUS ANTIBODY TESTING - HAVE WE ARRIVED?

Malcolm Richardson

Abstract: 

Chronic and allergic forms of pulmonary aspergillosis are estimated to affect over three million people 
worldwide. Anti-Aspergillus antibody detection (serology) has been performed for over 50 years for the 
diagnosis of different chronic Aspergillus infections, starting with aspergilloma and later with chronic 
necrotizing pulmonary aspergillosis. A wide variety of techniques have been used. Serology is also a 
cornerstone for defining allergic broncho-pulmonary aspergillosis (ABPA) and contributes to the initial 
diagnosis of Aspergillus-sensitized asthma patients without ABPA, to the follow-up of treatment or to the 
detection of exacerbations. Raised Aspergillus-specific IgG in chronic pulmonary aspergillosis and raised 
Aspergillus-specific IgE in allergic aspergillosis are characteristic of these diseases. For acute invasive 
aspergillosis, antibody detection has low utility compared to galactomannan antigen detection. Serology 
results have to be interpreted together with other clinical, radiological and biological, mycological criteria.

The diagnostic criteria of ABPA and chronic pulmonary aspergillosis are based on the patient’s immunological 
reactivity to crude extracts of Aspergillus fumigatus. However, because of cross-reactivity between crude 
allergen extracts from different fungi, apparent sensitization to crude A. fumigatus extracts does not always 
indicate genuine A. fumigatus sensitization. Recently, allergen components purified from the various morphological

 forms of fungi or produced as recombinant proteins have been introduced into a battery of new tests 
available for the diagnosis of allergic diseases, generally known as component-resolved diagnostics. More 
recently, molecular-based allergy diagnostics have been applied to fungal disease diagnostics.

Many methods exist to detect Aspergillus-specific antibodies, but there are limited published data regarding 
comparative efficacy and reproducibility. Recent studies have shown that the levels of IgE to Aspergillus 
allergens (Asp f1 and/or Asp f 2) can effectively differentiate ABPA from A. fumigatus-sensitized ashma. 
Using appropriate panels of Aspergillus allergens will also lead to an understanding of genuine versus cross- 
reactive sensitization in A. fumigatus-sensitized patients. It is anticipated that great strides will be made in 
fine-tuning antibody-based diagnostics for allergic and chronic aspergillosis. Serology is ‘on approach’ with 
an expected time of arrival in the not too distant future.

2016

Full conference title: 

7th Advances Against Aspergillosis