Endotyping Non IgE Mediated Immunoreactivity to Dermatophagoides farinae: Implications for Allergic Patients: A Retrospective Study

Background: Several publications report Dermatophagoides farinae allergens as responsible for several types of non–IgE-mediated allergic reactions. There is no standardized lab exam to endotype (quantify the participation of these mechanisms) in the context of allergic disease pathophysiology.

Aims: To evaluate the potential of the Leukocyte Adherence Inhibition Test (LAIT) and the Tube Titration of Precipitins (TTP) on serum to discriminate non–IgE-mediated immunoreactivity against D. farinae in patients with non–IgE-mediated allergic phenotype with clinically suspected hypersensitivity to their allergens.

Study Design: We retrospectively examined the medical charts of 134 allergic patients investigated with LAIT and 100 allergic patients investigated with TTP against an extract of D. farinae.

Place and Duration of Study: Instituto Alergoimuno de Americana – São Paulo – Brazil – between January 2018 and May 2024.

Methodology: The registered results of the semi-quantitative serum TTP against D. farinae extract were distributed in ranges through a cascade distribution chart to outline the variability of the results. The registered results of the percentage of Leukocyte Adherence Inhibition (LAI) promoted by the ex vivo challenges with D. farinae extract were distributed in ranges through a cascade distribution chart to outline the variability of results. The statistical characteristics of these cohorts were calculated.

Results: The TTP showed a wide distribution range, with four negative and most positive results concentrating on the higher dilutions. The mean was estimated at 1:242; the median was 1:128; the standard deviation was estimated at 1:210; the mode was 1:512 (appeared 36 times). The LAI ranged from 0% to 100%. The mean was 52%; the median was 55.5%; the standard deviation was 23.6%; the mode was 63% (appeared seven times). The cascade distribution demonstrates a wide range of LAI results.

Conclusion: Our preliminary results support that the semi-quantitative TTP and the LAIT have the potential to endotype and clinically discriminate diverse degrees of cellular and humoral non–IgE-mediated immunoreactivity against D. farinae in allergic patients.