In vitro evaluation of allergen potencies of commercial house dust mite sublingual immunotherapy reagents.
OBJECTIVE
The clinical efficacy of allergen-immunotherapy is known to be dose dependent. However, optimal maintenance dosage has not yet been determined for sublingual immunotherapy (SLIT). Furthermore, since companies adopt their own units for expression of allergenicity, the allergen concentrations of individual reagents cannot be compared easily. We sought to measure and compare the allergenicities of 3 commercially available house dust mite (HDM) SLIT regents and a subcutaneous immunotherapy reagent.


METHODS
We measured the HDM allergenic potency of the maintenance dosages of three SLIT reagents: Staloral® (300 index of reactivity [IR] /mL, recommended maintenance dosage [MD]: 120 IR), SLITone® (1,000 standard therapeutic unit [STU]/mL, recommended MD: 200 STU), Wolwopharma® (100 µg/mL, recommended MD: 20 µg), and subcutaneous immunotherapy regents of Hollister-Stier (10,000 allergy unit [AU] /mL). The allergenic potency was assessed by measuring the total protein concentrations, mite group 1 and 2 allergens using 2-site ELISA, and an inhibition test against IgE specific to Dermatophagoides farinae and Dermatophagoides pteronyssinus.


RESULTS
The protein content of the Wolwopharma® reagent was 1.5-261.4 times higher than that of the other 2 SLIT reagents. The concentration of group 1 major allergens in Staloral® (132.03 µg/mL) was 33- to 44.5-fold higher than in SLITone® (4.00 µg/mL) and Wolwopharma® (2.97 µg/mL). The concentration of group 2 major allergen was also 8.9- to 10.5-fold higher in Staloral® (15.7 µg/mL) than in SLITone® (1.8 µg/mL) or Wolwopharma® (1.5 µg/mL). An ELISA inhibition study against HDM-specific IgE showed that the allergen potency of Staloral® reagent is 8.5-fold and 21-fold higher than that of SLITone® or Wolwopharma®, respectively. The differences between the maintenance dosages are further exaggerated by the differences in the recommended volumes of SLIT reagents.


CONCLUSIONS
The allergen potencies of commercially available HDM SLIT reagents are markedly different. Consensus regarding the optimal allergen concentration for SLIT reagents used to treat HDM respiratory allergies is needed.
Department of Internal Medicine and Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Kyung Hee
KH
Park
Department of Internal Medicine and Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Mina
M
Son
Department of Internal Medicine and Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Soo-Young
SY
Choi
Department of Internal Medicine and Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Hey Jung
HJ
Park
Department of Internal Medicine and Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Jae-Hyun
JH
Lee
Department of Internal Medicine and Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Kyoung Yong
KY
Jeong
Center for Immunology and Pathology, Korea National Institute of Health, Osong, Korea.
Joo-Shil
JS
Lee
Department of Internal Medicine and Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Jung-Won
JW
Park
House dust mite; standardization; sublingual immunotherapy