In the present study, in-vitro IgE tests using molecular components represent important innovations in the diagnosis of rare diseases, such as inborn errors with HIE (Hyper-IgE). Thus, IgE sensitisation profiles can be evaluated, even in cases in which the patient’s cognitive defect does not allow for correct allergological classification. The use of allergen multiplex tests improves both, the management of skin pathology and the quality of life of the individual patients.
Here, a proteomic test combined with IgE testing were performed to study inborn errors with an atopic dermatitis-like clinical picture associated with a deregulated IgE response. Four patients with rare diseases, such as recessive X–linked ichthyosis, Comel–Netherton syndrome, monosomy 1p36 syndrome, and a microduplication of Xp11.4 associated with extremely high levels of IgE were evaluated by comparative genomic hybridisation microarray analysis and specific IgE evaluation using allergen macroarray (ALEX2) and allergen microarray (ISAC).
In patients suffering from atopic dermatitis, IgE reactivity to LTP-related food allergens was detected, impacting the quality of life. The avoidance of LTP-related foods from the diet resulted in a marked improvement of the patient’s clinical condition.
Furthermore, reactivity to CCDs (Cross-reactive carbohydrate determinants) was evidenced in one patient. Although sensitisation to CCDs has no clinical impact, it is important to remember that IgE testing without blocking CCD-specific IgE antibodies can give false IgE test results.
In another patient, reactivity to autoreactive allergenic components was shown. Interestingly, the patient was positive for both Asp f 6 and Ole e 9 considered to be a signature of patients with atopic dermatitis in the Mediterranean area.