Timothy Grass Pollen-Specific Immunoglobulin E in Nasal Secretions During Natural Allergen Exposure and After a Nasal Provocation Test in Patients with Suspected Local Allergic Rhinitis

Introduction: Allergic rhinitis (AR) imposes a substantial burden on individuals worldwide. Local allergic rhinitis (LAR) patients exhibit symptoms similar to those of AR without a positive skin prick test (SPT) or the presence of sIgE specific to one or more allergens. Our study evaluated specific and total grass pollen IgE in the nasal secretions of patients with suspected LAR, examining the effects of natural pollen exposure and nasal provocation testing (NPT). Methods: Twenty-nine subjects (18 with suspected LAR and 11 with AR) were included in this study. The total nasal symptom score (TNSS) and visual analog scale (VAS) were used for subjective assessment. NPT was performed using grass pollen allergen. Nasal lavage was used to obtain nasal secretions, and the levels of sIgE and total IgE were measured. Results: During the exposure vs. the off-exposure period, the TNSS and VAS were significantly higher in LAR (p < 0.0001 and p = 0.0061, respectively). sIgE and total IgE were significantly higher in the AR group than in the LAR group during the exposure period (p = 0.0008 and p = 0.0491, respectively). LAR diagnosis was confirmed in seven subjects. TNSS and VAS scores were higher after a positive NPT. The median level of sIgE was lower in the negative and positive NPT. A higher median total IgE level was observed post-provocation in both groups. A significantly higher median relative sIgE level was noted after positive and negative provocation (p = 0.0156 and p = 0.0143, respectively). Conclusions: The assessment of local sIgE levels in nasal secretions can be used as a method for the diagnostic workup of patients with suspected LAR. Achieving a well-defined and standardized protocol for the assessment of sIgE concentrations in nasal secretions of LAR is a goal of future larger studies.