Allergen Component Diagnosis of Patients with House Dust Mite Sensitization DOI: https://doi.org/10.1016/j.jaci.2018.12.718 Rationale The use of molecular allergy diagnostics may enhance specific allergen immunotherapy (AIT). Methods 437 patients aged 34.6±5.4 years, 56.1% males 43.9% females, were assessed over five months in 2018. The allergochip ALEX allowing major allergen component assessment was performed on patients sensitized to house dust mites, using Raptor Analysis MADx, (kUA/L). Results 106 (24.3%) were dust mite sensitized. Total serum IgE was elevated (294±4.3) in 89 (83.9%) individuals. Major components of D. Pteronyssinus seen were: Der p 2 – in 88 (83.1%); Der p 1 -in 48 (45.3%); Der p 23 – in 48 (45.3%); Der p 5 – in 25 (23.6%); Der p 7 – in 18 (17.0%); and Der p 11 – in 9 (8.5%) ; major components of D. Farinae: Der f 1 – in 67 (63.2%), Der f 2 – in 65 (61.3%); and tropomyosin Der p 10 in 9 (8.5%) of patients. Major components of Der p 2 and Der f 1 dominated, ranging from 0.12 kU/l to 38.2 kU/l, but 4 (3.8%) were sensitized only to Der p 5; 3 (2.8%) to Der p 23; 1 (0.9%) to Der p 11; and 9 (8.5%) co-sensitized to major components Der p 5, 7, 11 at higher levels (p<0.05) of sIgE, than to Der p 2 and/or Der p 1. Conclusions Patients with sensitization to house dust mites may have combinations of sensitization to Der p 1 and Der p 2 and sIgE to Der p 5, 7, 11 and 23 suggesting optimization of AIT may require presence of multiple allergen components. All Authors: A. Kurchenko G. Fedoruk · Bogomolets National Medical University, Kiev, Ukraine 1. S. YurievLawrence M. Dubuske Corresponding Author E-mail address:Claudiagray.paediatrics@gmail.com Division of Allergology, Red Cross War Memorial Children's Hospital, Cape Town, South Africa Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital, University of Cape Town, Cape Town, South Africa Correspondence Claudia Gray, Department of Allergology, Red Cross War Memorial Children's Hospital, Klipfontein Road, Cape Town 7700, South Africa Tel.: +27 21 4066889 Fax: +27 21 4066888 E‐mail: Claudiagray.paediatrics@gmail.com