Each of the 100 000 or so industrial chemicals on the European market must be separately tested for potentially harmful effects on humans. Common effects include cancer, hormone disruption and allergic reactions. Various methods allow testing for allergic effects caused by skin contact. However, some people can suffer an allergic reaction to chemicals as a result of inhalation. This form of reaction is technically known as respiratory chemical sensitisation (i.e. asthma attack), and for that no testing method has been available. The EU-funded GARDair project has developed the first test for respiratory sensitisation. The team evaluated and validated the test and has started the process of gaining regulatory approval. Researchers also prepared the test for launch on the international market.
Testing human cells
It is neither practical nor ethical to test chemicals directly on humans. Therefore, the GARDair procedure exposes cultured human cells to chemicals. If the cells react, this signifies an allergic response. “The method is based on an in vitro [test tube] cell system that mimics central parts of the human immune system,” says project coordinator Henrik Johansson. Separately for each chemical, researchers investigate genes from exposed cells and look for the signature expression of genes that indicates an immune reaction. The GARDair assay, or test, classifies candidate chemicals as respiratory sensitisers or non-sensitisers. The method also uses machine learning for pattern recognition in support of the final classification. The ultimate users of the assay would be companies manufacturing chemical, pharmaceutical or cosmetic products. These organisations are required by law to safety check their products, which includes checking for respiratory sensitisation. Academic research groups might also need to use the assay.
Trials went well. Other laboratories were consistently able to reproduce GARDair results, showing that the process has a high level of scientific validity. The development is a significant achievement. “Respiratory sensitisation has been notoriously difficult to assess,” adds Johansson. “The previous lack of an effective assay was not for lack of trying.” Immunological processes themselves are very complicated, as are methods for modelling them. Thus, the project’s achievements are all the more significant because no other group managed to get so far. The method is also completely free of animal experimentation. Studying human immune responses using human cells is the most direct and relevant way to approach the research. Furthermore, doing so uses a resource – human cells – that is affordable and abundant. The team will continue liaising with EU authorities to gain the necessary regulatory and legislative recognition of the new methods. Meanwhile, the GARDair assay has been launched and the first orders have been received. The team will continue developing strategies for marketing and communication. Most importantly, the GARDair assay will mean an accurate and affordable way of testing chemical products for potential allergic effects. It will also have secondary benefits for animal welfare, since the process eliminates the need for animal testing.
GARDair, assay, chemicals, respiratory sensitisation, human cells, animal testing, asthma, allergic reaction, respiratory chemical sensitisation, immune reaction, genetic tests