Background: Allergen extracts contain variable quantities of bacterial endotoxin. Recent studies have suggested that (1-->3)-beta-D-glucans (beta-glucans), also microbial cell wall components, may have adjuvant properties that could affect allergen immunotherapy.
Objective: To determine the quantities of beta-glucans in standardized allergen extracts.
Materials and methods: Ninety-four lots of 13 standardized allergen extracts were tested for beta-glucan content by Glucatell assay, and for endotoxin content by a specific, chromogenic formulation of the Limulus amebocyte lysate test.
Results: Standardized allergen extracts contain variable quantities of endotoxins and beta-glucans. As in our previous work, endotoxin activity was greatest in cat pelt and Dermatophagoides farinae, and least in the pollens. There was no correlation between endotoxin and beta-glucan levels (r = 0.1887; P = 0.07). beta-Glucan content was highest for grass pollen (median content, 10.6 ng/ml; range, 0.4-41.8 ng/ml), ragweed pollen (32.9 ng/ml; range, 6.5-41.2 ng/ml), and cat pelt (25.5 ng/ml; range, 16.7-41.1 ng/ml), and lowest for cat hair (4.9 ng/ml; range, 1.2-10.3 ng/ml), D. farinae (1.2 ng/ml; range, 0.4-5.2 ng/ml) and Dermatophagoides pteronyssinus (1.8 ng/ml; range, 0.4-6.7 ng/ml).
Conclusions: beta-Glucans are present in standardized allergen extracts. The effects of these quantities of beta-glucans on allergen immunotherapy and allergen skin testing require further study.