What has changed with subcutaneous immunotherapy against house dust mites? Eight-year, single-center real-world data.

Introduction: We aimed to investigate clinical and laboratory parameters that can predict clinical response in patients who completed subcutaneous immunotherapy (SCIT) against house dust mites (HDM) and to determine parameters associated with systemic adverse effects (SAE).

Methods: In total, 108 patients who had complete medical data were evaluated.

Results: Around 54.6% of patients were male; mean age was 11.7 ± 3.1 years. All patients had allergic rhinitis, 86% had asthma, and 22% had atopic dermatitis. After SCIT, mean symptom score (SS) for allergic rhinitis had decreased in 86% of patients, asthma severity had decreased in 35.5% of asthma patients. After SCIT, median eosinophil count and HDM skin prick test (SPT) diameters decreased, there was not statistically significant change in total IgE (P = 0.001, 0.001, and 0.824, respectively). No statistically significant difference was detected between the SS change groups (decreased, same, or increased) in terms of age, gender, disease duration, presence and severity of asthma, presence of atopic dermatitis, duration of SCIT, time after SCIT, initial sensitization status, total IgE, eosinophil and basophil counts, and SPT diameter for HDM. However, in the group with decreasing SS, total IgE change (in direction of decrease) was found to be statistically significantly higher (P = 0.008). SAEs were observed in 15.7% of patients, 0.41% of injections. SAEs were more common in girls (P = 0.023). Initial eosinophil count, basophil count, and dermatophagoides farina SPT diameter were statistically significantly higher in group with SAE (P = 0.007, 0.008, and 0.036, respectively).

Conclusion: HDM-specific SCIT is a treatment that provides reduction in allergic rhinitis symptoms and asthma severity in children. However, we could not identify any clinical or laboratory findings that could predict clinical success before treatment. Girls and patients with high eosinophil and basophil counts should be monitored more carefully for the development of SAE.