Molecular allergodiagnostics capabilities in determining the indications for allergen-specific immunotherapy with house dust mites allergen and its effectiveness in atopic dermatitis patients

BACKGROUND: Atopic dermatitis (AD) is a widespread chronic inflammatory skin disease, in the development of which complex genetic and immune mechanisms, environmental factors, allergens, are involved. An effective method of treating IgE­-mediated allergic diseases is allergen-­specific immunotherapy (ASIT), which affects all pathogenetically significant links of the allergic process. It is known that as a result of ASIT tissue sensitivity to an allergen, nonspecific tissue hyperreactivity and the intensity of allergic inflammation decrease, which testifies to the rearrangement of the cellular response from Th2 to Th1 with a corresponding change in the cytokine profile. Currently, dozens of scientific papers on the efficacy and safety of subcutaneous and sublingual ASIT in AD have been published; however, the question of the advisability of its appointment still remains unresolved.

AIM: To investigate the ASIT with house dust mite (HDM) allergens efficacy in AD patients, considering the results of molecular allergy diagnosis.

MATERIALS AND METHODS: The study was conducted as a prospective comparative open study, including 32 patients with AD (20 children and 12 adults), 90.6% were diagnosed with concomitant respiratory allergic diseases. Molecular allergodiagnostics was performed using microchip technology with purified natural or recombinant allergen components immobilized in the solid phase (Immuno­-Solid phase Allergen Chip, ISAC) to quantify allergen-­specific IgE (asIgE) against 112 allergen molecules from 51 allergen sources in one study (ImmunoCAP ISAC (Thermofisher, Phadia, Uppsala, Sweden). Patients were divided into two groups depending on the profile of molecular sensitization: with the presence or absence of asIgE to the major allergens of D. farinae and/or D. pteronyssinus Der p 1 (p 2) and/or Der f 1 (f 2). All patients passed three consecutive courses of subcutaneous ASIT with water­-salted HDM allergens produced by I.I. Mechnikov Biomed (Russia) under an accelerated scheme for 3 years. To assess the severity of the disease, the SCORAD indices, the Investigator’s Global Assessment (IGA), and the dermatological quality of life index (DLQI) were used.

RESULTS: Patients with sensitization to major allergens of D. farinae and/or D. pteronyssinus Der p 1 (f 1) and/or Der p 2 (f 2) more often achieved a significant improvement of AD symptoms according to the SCORAD index (OR 3.929, 95% CI: 0.879; 17.56), as well as they more often achieved IGA values of 1 or 0 after three courses of ASIT (OR 3.556, CI 95% 0.730–17.324) and more often assessed the effectiveness of ASIT as excellent and good in comparison with patients without sensitization to these components. The median and interquartile range of the DLQI index before treatment in group 1 was 17 [14; 20] points, in group 2 – 14 [12; 18], after the 3^rd course of ASIT: 6 [2; 10] and 8 [3; 10] points in groups 1 and 2, respectively. Adverse events were rare, their frequency did not significantly differ in both groups.

CONCLUSION: ASIT with HDM allergens is an effective and safe method of treatment of AD patients. Determination of the molecular spectrum of sensitization to HDM allergens components allows to justify the indications and predict the effectiveness of ASIT.