This 2018 German review provided short summaries of 44 studies on the contribution of histone modifications to allergies. An overall summary of their search results was:

“There are at least two levels at which the role of histone modifications is manifested.

• One is the regulation of cells that contribute to the allergic inflammation (T cells and macrophages) and those that participate in airway remodeling.
• The other is the direct association between histone modifications and allergic phenotypes.

Inhibitors of histone-modifying enzymes may potentially be used as anti-allergic drugs. Furthermore, epigenetic patterns may provide novel tools in the diagnosis of allergic disorders.”

This type of search is what’s expected of researchers who will perform either:

• A meta-analysis of studies selected from the search results; or
• Their own study.

These reviewers didn’t indicate that they were proceeding along either path.

The review was fine for the purpose of presenting current studies of the subject. But this was just the preparatory stage of research.

https://aacijournal.biomedcentral.com/articles/10.1186/s13223-018-0259-4 “Histone modifications and their role in epigenetics of atopy and allergic diseases”