Quantitative assessment of specific serum IgGs may verify source of environmental exposure in extrinsic allergic alveolitis (EAA)

Abstract

Abstract:  Assessment of humoral response to inhalation antigens is currently the most frequently used method to confirm exposure. It may be useful in extrinsic allergic alveolitis (EAA) patients, especially in cases that are unaware of the source of exposure. However, commercially available test may not include relevant antigens, which may lead to false negativity of the test. We proposed that testing patient serological responses to antigens from respectively environments might be useful in showing the relevance of these exposures. Ten patients diagnosed with EAA were included in the case-control study. Samples from potentially harmful environments were collected, and antigenic extracts were prepared and used for enzyme-linked immunosorbent assays (ELISA) to investigate serological responses to suspected antigens. Plasma samples of unexposed volunteers were used as controls. The results were interpreted in the context of other clinical findings when known (e.g., radiologic patterns, bronchoalveolar lavage fluid findings, histology results) and patient history. We suggest that environmental sampling may provide more information than previous history assessment and commercially available specific IgGs tests and helps to either reveal hidden exposures or find relevant exposure in cases with multiple potential sources. The results of these tests must be interpreted carefully in the context of other clinical data.

Keywords:

• extrinsic allergic alveolitis
• exposure
• antigen
• immunoglobulin G
• humoral response

PUBLIC INTEREST STATEMENT

Interstitial lung diseases including extrinsic allergic alveolitis are thought to share both genetic predisposition and environmental challenge. In patients with mainly inflammatory presentation of extrinsic allergic alveolitis, exposure might be the driver of the disease. While source of exposure is obvious in most of our patients, there is still no negligible group where we are not able to detect causative inhalation antigen. Taken into account that avoiding exposure remains the first and most important take-home message a patient should take away from a medical appointment, new methods how to find the source of exposure in these “hidden“ cases must be sought. Presented study shows a possible way, how to approach to antigen detection in patients with unknown source of exposure.

Competing interest

The authors declare no competing interests.

Additional information

Funding

The present study was supported by the Ministry of Health (Czech Republic) institutional support “Thomayer Hospital 00064190”, Czech Pneumological and Phthiseological Society grant and ROCHE grant G1207. Financial support was used to cover material, language editing and publication costs;Ministry of Health, Czech Republic [“Thomayer Hospital 00064190”];

Notes on contributors

Martina Sterclova

Our group is focused on interstitial lung diseases, namely extrinsic allergic alveolitis and idiopathic pulmonary fibrosis. The presented project concerns a very important part of our research devoted to environmental exposure and its effect on immune response and disease course modulation. Closely related are projects involving genetic predisposition to abnormal reaction of immune cells and respiratory system to inhalation antigens. A better understanding of factors predisposing to interstitial lung diseases, what drives the immune response and which factor predicts patients outcomes, would help us to choose a proper therapeutic approach.