Immunoreactivity against Dermatophagoides pteronyssinus Assessed by the Leukocyte Adherence Inhibition Test in Patients with Intrinsic Atopic Dermatitis and Correlated “Intrinsic” Non–IgE-mediated Allergic Conditions

Background: Due to the lack of standardized laboratory procedures able to demonstrate specific immune responses against the culprit allergens, the non—IgE-mediated allergy syndromes are a group of conditions diagnosed mostly by clinical examination and exclusion criteria. Objective: To evaluate the opportunity of the Leukocyte Adherence Inhibition Test (LAIT) to discriminate specific immunoreactivity against Dermatophagoides pteronyssinus (Dp) in a group of patients with non–IgE-mediated chronic allergic conditions. Methods: Ex vivo challenge tests performed with Dp were monitored by LAIT in patients presenting diverse non–IgE-mediated allergic conditions: intrinsic Atopic Dermatitis (iAD), intrinsic Allergic Rhinitis (iAR), intrinsic Ocular Allergy (iOA), intrinsic Chronic Pharyngitis (iCP), and intrinsic Asthma (iAS). Results: The mean LAI of the control group was 7%; the mean LAI of the iAR group was 34%; the mean LAI of the iCP group was 44%; the mean LAI of the iAS group was 45%; the mean LAI of the iOA group was 47%; the mean LAI of the iAD group was 55%. The non-parametric Wilcoxon-Mann-Whitney U test comparing the control group with each other group showed significance with p-value < α = 0.05 for all groups. Conclusion: The Leukocyte Adherence Inhibition Test is an easy, quick, and inexpensive ex vivo immunoassay with the potential to predict individual immunoreactivity against HDM allergens in real-world patients with non–IgE-mediated allergies.

Assessment of Immunoreactivity against Therapeutic Options Employing the Leukocyte Adherence Inhibition Test as a Tool for Precision Medicine

Background: The Precision Medicine’s approach employs the endotype concept as a central feature to personalize medical treatment. Individual immunoreactivity, alongside characteristics such as genetics, environment, and diet, is one of the factors that differentiates the therapeutic-driven endotypes. Objective: To evaluate the opportunity of the Leukocyte Adherence Inhibition test to differentiate the immunoreactivity between two similar therapeutic agents employed on Allergen Immunotherapy. Methods: Side by side Leukocyte Adherence Inhibitions tests were performed with ovalbumin and carbamylated ovalbumin on a population of 33 self-reported egg-allergic individuals. Results: The results showed two endotypes inside the immune response of the studied groups: The first endotype was defined by the 16 individuals that presented a significant decrease in ovalbumin’s immunoreactivity after carbamylation (mean of differences = 35%; p = 0.002). The second endotype was defined by 17 individuals that presented a significant increase in ovalbumin’s immunoreactivity after carbamylation (mean of differences = 32%; p = 0.001). Conclusion: The Leukocyte Adherence Inhibition test was able to differentiate two distinct immunoreactivity patterns when comparing two similar therapeutic agents suggesting, as proof of concept, a potential role to be employed as a Precision Medicine tool.

Abstract 17016: The Role of Polymerase Delta-Interacting Protein 2 in Pulmonary Vascular Inflammation

Introduction: Vascular inflammation is an underlying causative factor in the progression of various ailments including acute lung injury. In the inflamed lung, chronic endothelial cell (EC) activation facilitates leukocyte recruitment and extravasation into tissue beds, leading to end organ damage. Delineating the mechanisms of EC activation may uncover novel areas of therapeutic opportunity. Our laboratory has identified polymerase delta-interacting protein 2 (Poldip2) as a novel regulator of endothelial activation and permeability. Methods: Poldip2 +/- and +/+ mice were injected with either saline or lipopolysaccharide (LPS, 18 mg/kg) for either 6 or 18 hours to induce acute lung injury. Bronchoalveolar lavage (BAL) fluid was collected to assess leukocyte infiltration via flow cytometry and cytokine expression via ELISA. Evans blue staining was used to evaluate lung permeability, and tissue lysates were analyzed for inflammatory marker expression. For in vitro analysis, inflammatory marker expression, leukocyte adherence and cell permeability were tested in human pulmonary microvascular endothelial cells (HPMVECs) treated with saline or LPS (1 μg/mL). To test the efficacy of Poldip2 silencing in HPMVECs, siRNA was used at 100 nM (siControl vs siPoldip2). Comparisons between groups were analyzed with a one-way ANOVA followed by Tukey’s post-hoc test. Results: Compared to Poldip2 +/+, Poldip2 +/- mice treated with LPS exhibited significantly reduced mortality (80% vs. 20% survival), Evans blue staining, and leukocyte infiltration. FACS analysis of BAL fluid revealed a decrease in LPS-induced monocyte and neutrophil infiltration in Poldip2 +/- mice compared to Poldip2 +/+ mice. RT-qPCR analysis indicated a reduction in inflammatory gene induction in lung tissue. In HPMVECs, LPS induced increases in VCAM-1 protein expression, THP-1 leukocyte adherence and endothelial permeability, which were attenuated with siRNA-mediated knockdown of Poldip2 ( P<0.05 for all). Conclusion: Poldip2 is an important regulator of EC activation, leukocyte adherence and EC permeability. In scenarios of persistent vascular inflammation and endothelial barrier dysfunction, such as in acute lung injury, inhibition of Poldip2 may provide clinical benefit.