Eosinophils and rhinitis

Abstract

Summary Allergic rhinitis (AR) is typified by the nasal mucosal and luminal recruitment of eosinophils. These changes are evident in both seasonal and perennial disease, although the magnitude of these cellular changes is often greater with the more transient intense stimulation associated with seasonal allergen exposure than with the chronic persistent stimulation linked to perennial disease. Measures of eosinophil activation markers in nasal lavage such as eosinophil cationic protein and eosinophil protein X parallel the eosinophilic cellular changes and have been used serially to monitor allergic inflammation in association with intranasal allergen challenge and in therapeutic intervention studies. In both naturally occurring disease and laboratory allergen challenge, there is considerable inter‐subject variability in the magnitude of eosinophil airway recruitment and activation. Studies evaluating the mechanisms involved in nasal eosinophil recruitment identify systemic involvement of bone marrow stimulation and tissue recruitment of circulating progenitor cells. Interleukin‐5 (IL‐5) is a key cytokine involved in this process, acting on both marrow and circulating progenitors, with chemokines such as stromal cell derived factor‐1, RANTES (regulated on activation, normal T cell expressed and secreted) and eotaxin potentially being involved in tissue uptake and localization within the nasal airways. Inflammatory mediators such as leukotrienes acting through the cys‐LT1 receptor, in conjunction with IL‐5, and prostaglandin D2 acting through eosinophil‐expressed DP and CRTH2 cell surface receptors also contribute in animal models of allergic inflammation. The function of nasal eosinophils in AR can be debated. Genetic and nasal challenge models, with chemokines that promote eosinophil influx, support the relevance of eosinophils to symptom expression in rhinitis while the timing of the eosinophil recruitment following intranasal allergen challenge, the relationship between eosinophils and plasma protein exudation as well as the appreciation that clinical disease expression can arise in the apparent absence of nasal eosinophilia favour a restorative function for this cell. In the absence of specific eosinophil‐targeted intervention in rhinitis, it is not possible to conclusively apportion the relative involvement of eosinophils in these inductive and restorative processes but it has to be appreciated that the close association between eosinophils and clinical disease expression in rhinitis is not necessarily causal.

Serum vitamin D and immunoglobulin E levels in children of allergic rhinitis: a case-control study from Central India

“…20 Infiltration of inflammatory cells is evident in both seasonal and perennial form, though the magnitude of these cellular changes is somehow different in seasonal and perennial AR. 21 In our study, the study group with AR had significantly higher mean level of serum IgE as compared to the control group. Similar results were found in the study conducted by Angelo et al 22 The study conducted by Rene et al contradicts the outcome of our study and shows that high IgE levels did not have correlation with the higher frequency of concurrent infections.…”

Individualized Treatment of Allergic Rhinitis According to Nasal Cytology

“…Most drugs (corticosteroids, anti-leukotrienes, and anti-histamines) are focused on controlling eosinophilic inflammation in the treatment of AR. 4 5 Recently, researchers have explored the role of neutrophils in allergic inflammation and disease, especially in severe asthma patients. 6 The high-affinity receptors for immunoglobulin E (FcɛRI) are expressed on human neutrophils in asthma, which may be enhanced by stimulation with specific allergens.…”

Assessment of cost effectiveness of antihistaminics in allergic rhinitis patients in rural region by Nasal cytology: a simple and inexpensive tool

“…10 Infiltration of inflammatory cells is evident in both seasonal and perennial form, although the magnitude of these cellular changes is somehow different in seasonal and perennial allergic rhinitis. 11 Although the type of infiltrating cells and pattern of inflammation is varied among different studies but generally accepted, allergic rhinitis (AR) is characterized the recruitment of eosinophils into the nasal mucous. Increased numbers of eosinophils are reported within nasal lavage.…”