Contribution of the Leukocyte Adherence Inhibition Test to the Diagnosis of Innate Non–IgE-mediated Immunoreactivity against Saccharomyces cerevisiae

Aims: To evaluate the potential of the Leukocyte Adherence Inhibition Test (LAIT) to discriminate non–IgE-mediated innate immunoreactivity against Saccharomyces cerevisiae in patients with clinical suspicion of allergic reaction to fungal allergens.

Study Design: We retrospectively examined the medical charts of 200 allergic outpatients with urticaria and/or atopic dermatitis associated with the ingestion of fermented food. The individuals were selected by being investigated with an ex vivo challenge monitored by LAIT against an extract of S. cerevisiae after undetectable specific IgE and not reactive allergic skin tests to this allergen.

Place and Duration of Study: Instituto Alergoimuno de Americana – São Paulo – Brazil – between January 2018 and August 2023.

Methodology The percentage of Leukocyte Adherence Inhibition (LAI) promoted by the ex vivo challenges with S. cerevisiae extract was distributed in ranges through a cascade distribution chart to outline the variability of the results.

Results: The mean LAI was 52.5%; SD 24.7%, ranging from 0% to 98%; modes = 0% and 61% (each appeared six times). The cascade distribution chart showed a wide range of LAI results, suggesting that some patients had immunoreactivity against the S. cerevisiae allergens while others did not.

Conclusion: Our preliminary results support the conclusion that the ex vivo challenges with S. cerevisiae monitored by the LAIT can differentiate diverse degrees of non–IgE-mediated immunoreactivity against their antigens in allergic patients.