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

Aims: To evaluate the potential of the Leukocyte Adherence Inhibition Test (LAIT) to discriminate innate immunoreactivity against Alternaria alternata in patients with clinical suspicion of allergic reaction to fungal allergens.

Study Design: We retrospectively examined the medical charts of 100 patients diagnosed with Allergic Rhinitis and/or Asthma with clinical suspicion of fungal hypersensitivity who were investigated with an ex vivo challenge monitored by LAIT against the extract of A. alternata.

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 A. alternata extract was distributed in ranges through a cascade distribution chart to outline the variability of the results.

Results: The mean LAI was 50%; SD 22,2%, ranging from 0% to 94%; mode = 58% (appeared five times). There was a wide range of distribution of LAI results, suggesting that some patients had immunoreactivity against the A. alternata allergens while others did not.

Conclusion: Our preliminary results support that the LAIT performed with A. alternata may differentiate diverse degrees of ex vivo immunoreactivity against this airborne antigen in allergic patients.