Cat and dog allergies
In general, the severity and progression of cat and dog allergies
involve IgE recognition of a progressively increasing number of
components from the sensitizing allergen source (molecular
spreading)30,62-65.
The availability of CRD for different cat and dog allergens has also
raised the possibility of more precisely targeted AIT, mainly because it
may distinguish primary sensitization from cross-sensitization, thereby
enabling selection of the primary sensitizing allergen source for
therapy.
In a recent, comprehensive study66, including most of
the components available, the pattern of IgE sensitization to cat
allergens showed that 92% of cat-allergic patients had positive IgE
antibodies results to Fel d 1. Other allergens also seem important, such
as Fel d 4 and Fel d 7. Previous studies reported similar results67. The content of Feld
d 1 in allergenic extracts varies substantially. Nevertheless, it has
been demonstrated that the maintenance efficacy dose of Fel d 1 is 15
mg/ml68.
In the same study, in patients with dog allergy, 52.4% were positive to
Can f 1, and 57.2% to Can f 5. The most frequent monomolecular
sensitization was to Can f 5.
The content of different dog allergen molecules in European AIT extracts
has been recently studied69. These authors
demonstrated great variability in extracts from five companies and
scarce content of major allergens70.
In general, AIT with cat extracts yield better clinical results than
with dog ones. The higher complexity of dog allergy sensitization
patterns, the lack of preparations with an adequate balance of major
allergens is likely to explain this divergence66,71,72.
Further studies are needed to determine whether CRD could be used to
identify patients who are most likely to respond to AIT specially in dog
allergy.
Figure 5 summarizes decision-making algorithms in cat and dog allergy
AIT selection.