Allergen content and sensitization profiles determine IgE in vitro potency of German cockroach extracts
Published online: August 28, 2018
Cockroach allergy is an important public health problem in the United States. Chronic exposure to potent cockroach allergens results in IgE sensitization to multiple allergens which often leads to the development of asthma. Cockroach extracts for immunotherapy are currently not standardized and are of variable potency. Several new cockroach allergens have been identified in recent years whose importance in cockroach allergy needs to be established.
In an original article recently published in The Journal of Allergy and Clinical Immunology (JACI), Glesner and colleagues addressed the variability in: a) allergen content of German cockroach extracts, and b) the subject’s IgE sensitization profile to eight cockroach allergen components, as determinants of in vitro extract potency for IgE reactivity. The variability in allergen content poses a challenge for standardizing and manufacturing extracts with consistency for clinical use.
Twelve German cockroach extracts prepared from different sources using different protocols were analyzed for allergen content (Bla g 1, Bla g 2 and Bla g 5), and for their potency to inhibit IgE antibody binding to a reference extract for 5 highly cockroach allergic subjects. The IgE profile of cockroach-sensitized subjects was also assessed using streptavidin ImmunoCAPs, each loaded with a purified recombinant allergen (from groups 1, 2, 4, 5, 6, 7, 9 and 11).
Allergen levels in cockroach extracts were highly variable. IgE sensitization profiles were unique per subject, without immunodominant allergens. Three new major allergens (from groups 6, 9 and 11), were identified among highly cockroach-sensitized subjects. The eight allergens analyzed account for a large proportion of cockroach sensitization. In vitro IgE potencies varied among different extracts per subject, and among subjects for each extract.
The in vitro potency of German cockroach extracts for IgE reactivity depends on allergen content and allergen-specific IgE titers of the cockroach-allergic subject. These two factors are relevant for selection of optimal extracts to be used for immunotherapy and should be considered for the design and interpretation of data from cockroach immunotherapy trials.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.
Allergen content in German cockroach extracts and sensitization profiles to a new expanded set of cockroach allergens determine in vitro extract potency for IgE reactivity
J Glesner, BS, S Filep, BS, LD Vailes, MS, S Wünschmann, PhD, MD Chapman, PhD, G Birrueta, BS, A Frazier, PhD, KY Jeong, PhD, C. Schal, PhD, L Bacharier, MD, A Beigelman, MD, P Busse, MD, V Schulten, PhD, A Sette, Dr. Biol. Sci., A Pomés, PhD