To the Editor,
We read with great interest your chapter from the EAACI Molecular
Allergology User´s Guide 2.0, entitled: Dust mite allergy [1]. The
development of Component Resolved Diagnosis (CRD) has efficiently
contributed to identify genuine sensitization to a panel of eliciting
allergens, thus allowing subsequent clinical decisions to an
individualized therapy. Given that two possible decision algorithms have
been proposed for mite allergy in both temperate and tropical countries
-including 4 and 7 individual molecules, respectively- several
complementary considerations could be addressed.
Firstly, since environmental variations, in climate warming and
industrialization are becoming a more globalized concern, changes in the
human allergen exposome are likely expected. Moreover, it has been
speculated that these changes may affect mite metabolism, leading to an
increased indoor allergen production worldwide and possibly a shift in
their species [2]. This is the case for Blomia tropicalis andLepidoglyphus destructor (Glycyphagoidea family), formerly
considered as marginal storage mites with a limited allergenic
cross-reactivity with Pyroglyphidae mites, but currently showing as
relevant markers for atopic disease under specific weather conditions
[3]. As atopic pheno-endotypes are steadily evolving under a
changing allergen exposome, a decision approach -including an algorithm
with a larger number of commercially available individual molecules as
Der p 5, Der p 7 and/or Der p 21- is specially warranted in those
locations with a preponderant rate (up to 80%) of polysensitized
subjects suffering from allergic rhinitis and/or asthma (Figure 1). In
addition, as polysensitization has a confirmed impact on the clinical
expression and severity of allergic disease [4], the inclusion of
Lep d 2 from Lepidoglyphus destructor in our proposed
algorithm (Figure 2) may be of interest not only under tropical and
subtropical climate conditions but also the as a potential emerging
allergen source in temperate countries [5].
Secondly, the description of locally serodominant allergens -Der p 7-
and the subsequent identification of clinically relevant allergens
-i.e., IgE binding molecules as Der p 5 with a defined allergenic
activity- is nowadays paving the road to a personalized management of
allergic diseases. Despite a perfect molecular matching between
patient´s IgE sensitization profile and allergen immunotherapy (AIT)
composition is ideally sought, a wide range of variations in the
representation of individual molecules in an extract is currently
allowed according to European guidelines [6]. In this regard, CRD
has greatly contributed to improve success of AIT only for those house
dust mite (HDM)-allergic patients who were exclusively sensitized to
specific molecules -i.e. Der p 1 and/or Der p 2- but not for patients
with a sensitization to other HDM allergens [7]. Therefore, the use
of standardized extracts of good quality with documented clinical
evidence -i.e. proven safety and efficacy- comprising those relevant
molecules present in the local allergen exposome, highlights the
importance of individualized care to AIT success. In fact, despite Der p
1, Der p 2 and/or Der p 23 account for more than 80% of the specific
IgE to Dermatophagoides pteronyssinus [1], the absence of
evidence regarding a concurrent sensitization to the so-called mid-tier
allergens -i.e Der p 5, Der p 7 and/or Der p 21- may not be considered a
formal contraindication for AIT in selected cases.
Provided that AIT is still used in less than 10% of subjects with
allergic respiratory diseases [6], the progressive availability and
knowledge of allergenic molecules favors a better understanding of the
different sensitization profiles to benefit a broader number of patients
from the only potential disease-modifying therapy.
Ruperto González-Pérez1,2, Paloma
Poza-Guedes1,2, Fernando Pineda3
1 Allergy Department, Hospital Universitario de
Canarias, Tenerife, Spain.
2 Severe Asthma Unit, Hospital Universitario de
Canarias, Tenerife, Spain.
3 Inmunotek SL Laboratories, Madrid, Spain.