House dust mites: the insidious symbiosis

Aim: to assess changes in the patterns of sensitization to house dust allergens in a cohort of children with allergic disorders over the last 30 years. Patients and Methods: this retrospective analysis included 26,343 protocols of allergy tests to house dust and its allergenic components (house mix, D. pteronyssinus and D. farinae mites, library dust) that had been carried out in children 4–18 years old over the period from 1989 to 2019. Skin testing was performed using the generally accepted scarification technique on the anterior surface of the forearm through a drop of the tested allergen. Then, the test results are assessed by visual inspection with a score of 1 — 4. The results of continuous monitoring were summarized and statistically processed for all years of the observation period, but the article presents analysis of the "cross-section" indicators only for those years that were convenient for comparison. The authors calculated a percentage ratio of the number of patients sensitized to the studied allergen to the total number of patients tested for hypersensitivity to this allergen during a particular year. Then, they compared the percentage of patients with low (1–2) and high (3–4) scores. Results and Discussion: the analysis showed a steady increase in IgE hypersensitivity to the house dust mix (from 23.7% in 1989 to 71.2% in 2019). Also, it demonstrated an increase in the degree of sensitization (3 — 4 scores) to the integral dust mix (from 4.2% in 1989 to 16.6% in 2019), which was significantly higher than that to the dust mites themselves due to the diverse composition of specific proteins of epidermal, fungal, bacterial, and insect origin that can induce antibodies independently on each other. There was a similar 2.6-fold growth in sensitization to the library dust over the first 10 years of observation, and by 2019 hypersensitization developed in 57.2% of children from this cohort. However, a dramatic decline in high scores (3–4) of the detected level to 5% was reported in 2019 which was associated with the changes in the ways of in-house data storage. Conclusion: the study findings provide a rationale for the mandatory control of dynamic changes in sensitization among children with allergic disorders using an expended household allergen panel. The steady increase in sensitization to house dust allergens confirms a low effectiveness of elimination measures and suggests a progressive immune imbalance under the everyday pressure of urban ecology. KEYWORDS: children, house dust, allergens of house and library dust, household sensitization, mites. FOR CITATION: Bardenikova S.I., Rychkova T.I., Kulikova E.V. et al. House dust mites: the insidious symbiosis. Russian Medical Inquiry. 2023;7(2):89–95 (in Russ.). DOI: 10.32364/2587-6821-2023-7-2-89-95.