Hypersensitivity Pneumonitis of Domestic Origin: Investigation of the Microorganisms Involved and Improvement of Serological Diagnosis.

Hypersensitivy pneumonitis (HP) are chronic respiratory diseases due to frequent exposure to high quantities of allergens (molds, bacteria, mycobacteria, avian proteins). In case of domestic HP, patients are exposed at home to molds due to flooding or poor ventilation.

The diagnosis of domestic HP includes detection of IgG towards molds. A prior study in 2005 allowed the determination of frequent allergenic molds isolated in homes in Bourgogne Franche Comte (study on 110 dwellings). However, no real cohort of proven cases versus controls is available. So, we are lacking validated thresholds. The HOME HP study is a prospective study that will include several centers of pneumology on France territory. The fungal contamination of dwellings occupied by patients suffering of interstitial disease (DIP), including suspicion of domestic HP, will be analyzed. The most frequently isolated molds will be then produced as antigens and will be tested in order to assess the sensitization of the included patients. The data of imagery, BALF cytology will allow to determine if patients are diagnosed with domestic HP or not. We will then obtain 2 groups of patients 1-proven domestic HP and 2-non domestic HP . Comparing the number of immunization arcs between the 2 groups will then be possible to validate appropriate thresholds for the serodiagnosis of domestic HP.

Domestic HP are rare diseases, so a high number of inclusions will be needed to obatin in 2 years about 25-30 proven cases. The HOME HP study is important to improve the serodiagnosis of domestic HP.