Abstract
Background: Recent studies indicated that fish-allergic
patients may safely consume certain fish species. Multiplex IgE testing
facilitates the identification of species tolerated by individual
patients.
Methods: Sera were collected from 263 fish-allergic patients
from Austria, China, Denmark, Luxembourg, Norway and Spain. Specific (s)
IgE to parvalbumins (PVs) from 10 fish species along with IgE to 7 raw
and 6 heated fish extracts was quantified using a research version of
the ALEX2 assay. IgE-signatures of individual patients
and patient groups were analyzed using SPSS and R.
Results: sIgE to alpha-PV from ray, a cartilaginous fish, was
not detected in 78% of the patients while up to 41% of the patients,
depending on their country of origin, tested negative for at least one
beta-PV. sIgE values were highest for mackerel and tuna PVs
(>10 kUA/L) and significantly lower for cod (4.9 kUA/L) and
sole PVs (2.55 kUA/L). 17% of the patients, although negative for PVs,
tested positive for the respective fish extracts. Based on the absence
of IgE to PVs and extracts, up to 21% of the patients were identified
as potentially tolerating one or more bony fish. Up to 90% of the
patients tested negative for ray. The probability of negativity to one
fish based on negativity to others was calculated. Negativity to tuna
and mackerel emerged as a good marker of negativity to additional bony
fish.
Conclusion: Measuring sIgE to PVs and extracts from
evolutionary distant fish species indicates bony and cartilaginous fish
species for tolerance-confirming food challenges.
Keywords: fish allergy, fish tolerance, multiplex allergy
diagnosis, parvalbumin, fish extracts