The role of the immune system in eosinophilic diseases

Eosinophilic disorders include a broad and varied spectrum of diseases. The common clinical feature linking these disorders is a peripheral blood count of 300 cells/mm3 or greater in the absence of a secondary cause, with clinical manifestations ascribable to eosinophilia. Eosinophils are cells from the innate immune system originating from bone marrow progenitors, and they can be distinguished into circulating and resident eosinophils. Eosinophilia is frequently associated with immune deficiency or immune dysregulation disorders.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare eosinophilic disorder, characterized by the presentation of asthma, high levels of eosinophils, and vasculitis. In EGPA, there is a dysregulation of the Th1/Th2 balance, with a shift towards a Th2-dominant immune response. This imbalance leads to the activation and recruitment of eosinophils to the tissues, which can cause tissue damage and inflammation. Eosinophilic asthma with CRwNP is a subtype of asthma that is also associated with elevated levels of eosinophils and a Th2 immune response. Patients with EGPA may also have a history of asthma and/or chronic rhinosinusitis with nasal polyps, which may be related to the underlying immunological dysregulation.

Immense progress has been made in deciphering the role of eosinophils in disease pathology but there are still scarce data about the role of the immune-mediated system in the pathogenesis and/or the severity of the course of eosinophilic diseases. While the imbalance of the Th2 axis in immunodeficiencies with eosinophilia is well-known and well-described in the literature, there is growing evidence to suggest that other T cell subsets may also play a role in the pathogenesis of these diseases. For example, recent studies have suggested that regulatory T cells (Tregs) also play a role in the development of eosinophilic disorders. Tregs are a subset of T cells that play a critical role in regulating immune responses and preventing autoimmunity. However, in some cases, dysregulation of Tregs has been implicated in the pathogenesis of certain eosinophilic disorders, such as hypereosinophilic syndrome.
Further research is needed to better understand the role of these and other T cell subsets in eosinophilic disorders, as well as the mechanisms by which they contribute to disease pathogenesis. This could lead to the development of new targeted therapies for these disorders, which may be more effective and have fewer side effects than current treatment options.

We, therefore, welcome the submission of Original Research and Review articles that cover, but are not limited to, the following sub-topics:
• Eosinophils biology and their interaction with other immune and non-immune cells
• Hemostatic (resident) and inflammatory eosinophils in the gastrointestinal tract and airways
• Eosinophilic asthma and chronic rhinosinusitis
• Medication and toxin-related eosinophilia
• The role of eosinophils in infectious diseases, and hematologic and neoplastic disorders
• Primary immunodeficiency and immune dysregulatory syndromes with eosinophilia
• Immunopathogenesis and clinical presentation of eosinophilic cutaneous disorders, eosinophilic gastrointestinal disorders, and hypereosinophilic syndrome
• Role of T reg cells in eosinophilic diseases

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Posted on

August 30, 2020