Can Serum-Specific IgE/Total IgE Ratio Predict Clinical Response to Allergen-Specific Immunotherapy in Children Monosensitized to House Dust Mite?

Background. Allergen-specific immunotherapy (SIT) is one of the important regimens for the treatment of allergic diseases. Predictive tests for the clinical response to SIT are limited. In this study we aimed to evaluate whether specific IgE/total IgE levels can predict clinical improvement in monosensitized patients to house dust mite treated with immunotherapy. Patients and Methods. We analyzed 32 patients who had undergone 2 years of SIT. Serum t-IgE and s-IgE levels, and serum s-IgE/t-IgE ratios were calculated and tested for correlation with clinical response to SIT. Asthma symptom score (ASS), rhinitis symptom score (RSS), pulmonary functions and visual analogue scales (VAS) were evaluated at the beginning and after 2 years. Results. There were 17 boys and 15 girls with the mean age of 10.78 ± 3.03 years. The mean serum house dust mite s-IgE level was 128.62 ± 142.61 kU/L, t-IgE 608.90 ± 529.98 IU/mL, and s-IgE/t-IgE ratio 33.83 ± 53.18. Before immunotherapy, ASS was 6.23 ± 1.63, RSS; 8.20 ± 1.88, VAS; 7.38 ± 2.01, FEV1 (%); 89.14 ± 8.48, PEF (%); 88.93 ± 13.57, and after 2 years, these values were determined as 1.90 ± 1.10, 3.05 ± 1.39, 1.35 ± 1.24, 97.6 ± 11.26, and 97.0 ± 11.55, respectively. s-IgE/t-IgE ratio was correlated with change in RSS (r = -0.392, P = 0.08) and VAS (r = -0.367, P = 0.05). Conclusion. Although SIT is very effective treatment, all patients do not benefit from treatment. We assumed that s-IgE/t-IgE ratio would be useful to predict the clinical response to SIT.