A WAO — ARIA — GA2LEN consensus document on molecular-based allergy diagnosis (PAMD@): Update 2020

Abstract

Precision allergy molecular diagnostic applications (PAMD@) is increasingly entering routine care. Currently, more than 130 allergenic molecules from more than 50 allergy sources are commercially available for in vitro specific immunoglobulin E (sIgE) testing. Since the last publication of this consensus document, a great deal of new information has become available regarding this topic, with over 100 publications in the last year alone. It thus seems quite reasonable to publish an update. It is imperative that clinicians and immunologists specifically trained in allergology keep abreast of the new and rapidly evolving evidence available for PAMD@. PAMD@ may initially appear complex to interpret; however, with increasing experience, the information gained provides relevant information for the allergist. This is especially true for food allergy, Hymenoptera allergy, and for the selection of allergen immunotherapy. Nevertheless, all sIgE tests, including PAMD@, should be evaluated within the framework of a patient's clinical history, because allergen sensitization does not necessarily imply clinical relevant allergies.

Egg Allergy: Diagnosis and Immunotherapy

“…Gal d 2 is the most abundant protein and constitutes 54% of the total egg white protein; however, Gal d 1 is found to be the most allergenic and dominant among patients (Table 2) [28]. The production of sIgE towards heat and acid-stable proteins, such as Gal d 1, is generally associated with a greater risk of systemic and or severe reactions [49]. Contrastingly, patterns in heat-labile proteins, such as Gal d 2, are commonly associated with a lower risk of severe allergic presentations.…”

“…However, the involvement of IgG as an effector mechanism of food allergen-induced allergic reaction is still under question. In 2020, the WAO stated that "more studies are needed to define specific IgG as a marker of food allergy" [49].…”

“…However, the involvement of IgG as an effector mechanism of food allergen-induced allergic reaction is still under question. In 2020, the WAO stated that "more studies are needed to define specific IgG as a marker of food allergy" [49]. Once the allergen is processed and presented by the APC's to the Th0 cells, the Th0 cells differentiate into Th2 cells in allergic individuals.…”

“…It is difficult to determine with certainty the exact window of allergic sensitization, but population-based birth cohort studies indicate that allergic sensitization occurs early-on in childhood [63]. Consequently, the process in which allergic sensitization occurs, including antigen presentation, T-cell and the immunoglobulin class switch toward IgE, is difficult to study in great detail [49]. Studies performed on animal models indicate the possibility that other cells, such as follicular dendritic cells (FDCs), are also involved in early sensitization [64].…”

“…This along with the utilization of DNA technology has piloted a new chapter of diagnostics, allowing allergic molecules to be characterized and cloned to determine various allergic diseases. The growing availability of allergenic molecules has introduced a new phase in diagnostics, now termed precision allergy molecular diagnostic applications (PAMD@), allowing for greater management of the allergic disease [49].…”