High-resolution transcriptomic and proteomic profiling of house dust mite homologous allergens

House dust mites (HDM) produce an unparalleled diversity of indoor allergens, yet their allergen composition has been inferred mostly from transcriptomes rather than proteins. METHODS: The homologous allergen proteins were identified and phylogenetically analyzed in HDM, stored-product, parasitic, herbivorous, and soil-living mites. Using high-sensitivity mass spectrometry, we generated a comprehensive protein-level allergome for Dermatophagoides farinae and Dermatophagoides pteronyssinus, identifying ~191 putative homologous allergens, including variants and proteome sequences of undetermined genomic origin, assigned to 40 of the 44 currently recognized HDM allergen groups and 2 groups of Tyrophagus putrescentiae allergens (Tyr p 35 and Tyr p 36). Blo t 12 was not detected, and Blo t 19 and Der f 17 were excluded from analyses; Blo t 41 was suggested as Gr_23. The set of allergen groups is conserved between HDM species, but the number of variants and abundance differ markedly between species, as well as protein fractions from mite bodies and feces. In the feces proteome, the most abundant allergen groups in D. farinae were cysteine protease (Gr_1), NPC2 family proteins (Gr_2), and C2 domain-containing protein (Gr_36), which were less abundant in D. pteronyssinus. Although trypsins (Gr_3/6/9) had the same intensity as in D. farinae, they formed the allergen spectrum of D. pteronyssinus feces. Body and fecal proteome profiles were not significantly correlated (Spearman correlation), suggesting that mite bodies and feces are not interchangeable allergen sources. This may be relevant for commercial vaccines and diagnostic sets, which are based on mixtures of feces and bodies, so that their allergen profile depends on the proportion of these components.