Published January 2017
Journal of Clinical Immunology

Children exposed to mold, fungus and mildew in their homes and communities are more likely to develop asthma than non-exposed children. This can be so severe that their asthma is difficult to treat or develops resistance to standard therapies and anti-inflammatory steroids.

A new study finds that children with high values on the Environmental Relative Moldiness Index (EMRI) scale do not have to be allergic to mold or fungus for severe asthma to develop. Cincinnati asthma specialists are recommending a new protocol for these difficult-to-treat patients, including renewed efforts to reduce childhood exposure to fungus and mold.

“What our study found is that children can have mold or fungal exposure that’s very detrimental to their asthma, even if they’re not sensitive to the mold,” says Gurjit Khurana Hershey, MD, PhD, director of the Division of Asthma Research. “We found that even spores and fragments of mold can cause asthma symptoms.”

Difficult-to-treat asthma accounts for more than 50 percent of asthma healthcare utilization. The new study compared data from the Cincinnati Childhood Allergy and Air Pollution Study (CCAPS), and laboratory tests that measured immune responses in mice exposed to various levels of mold, fungus and b-Glucan, a component of mold cell walls. Researchers looked for high immunologic levels of IL-17-A, a cytokine linked to inflammation, and TH2 and TH17 helper cells, implicated in steroid-resistant responses.

Fungal exposure—even to spores or components of  mold—can promote more severe asthma symptoms and steroid resistance, the study found.

Hershey and her team suggest that subgroups of asthmatic patients with high fungal exposure and mixed TH2/Th17 responses might benefit from anti-IL-17A therapy alone or in combination with steroids.