Diagnosis of immunoallergenic pathologies due to microorganisms such as hypersensitivity pneumonitis includes
detection of circulating specific antibodies. Detection of precipitins has classically been performed using immunoprecipitation
techniques with crude antigenic extracts from microorganisms implicated as etiologic agents. However, these
techniques lack standardization because of the different composition of fungal antigenic extracts from one batch to another.
Therefore, there is high interest in developing standardized serological diagnostic methods using recombinant antigens.
Immunoproteomics have proved to be useful for identifying the immunogenic proteins in several microorganisms
linked to hypersensitivity pneumonitis. With this approach, the causative microorganisms are first isolated from the environment
of patients. Then the proteins are separated by two-dimensional electrophoresis and revealed by Western blotting
with sera of different patients suffering from the disease compared to sera of asymptomatic exposed controls. Immunoreactive
proteins are identified by mass spectrometry. Identified immunoreactive proteins found to be specific markers for
the disease could be subsequently produced as recombinant antigens using various expression systems to develop ELISA
tests. Using recombinant antigens, standardized ELISA techniques can be developed, with sensitivity and specificity
reaching 80% and 90%, respectively, and more if using a combination of several antigens. Immunoproteomics can be applied
to any environmental microorganisms, with the aim of proposing panels of recombinant antigens able to improve the
sensitivity and standardization of serologic diagnosis of hypersensitivity pneumonitis, but also other mold-induced allergic
diseases such as allergic broncho pulmonary aspergillosis or asthma.