Asthma Immuno Flashcards
What are the fundamental pathophysiological features of asthma?
- Airway hyperresponsiveness
- Inflammation
- Structural changes in the airway wall
- Development of allergic sensitization
These features are key to understanding asthma and its progression, especially in pediatric cases.
What is the role of airway hyperresponsiveness in asthma?
It can manifest as reversible airflow obstruction
This feature is a key characteristic of asthma and contributes to its symptoms.
What initiates the development of allergic sensitization in asthma?
Allergen exposure at mucosal or barrier surfaces
The pulmonary epithelium is the first point of contact for allergens.
What is the role of dendritic cells (DCs) in asthma pathogenesis?
DCs recognize and uptake antigens, migrating to lymph nodes to present them to naive T cells
This process is crucial for the activation of T cells and the subsequent immune response.
What cytokines do type 2 T helper cells (Th2) release during an allergic reaction?
- IL-4
- IL-5
- IL-13
These cytokines are essential for driving allergic inflammation and are characteristic of asthma.
What is the significance of IL-5 in asthma?
It promotes eosinophil differentiation, growth, and survival
Eosinophils are a hallmark feature of the asthmatic immune response.
What is the predominant airway inflammatory phenotype in pediatric asthma?
Eosinophilic
This phenotype is independent of disease severity or duration.
How do glucocorticoids affect eosinophils in asthma treatment?
They increase eosinophil apoptosis and block the survival effect of IL-5
This results in a reduction in airway eosinophilia with steroid therapy.
What role do mast cells play in asthma?
They degranulate upon allergen exposure, releasing mediators that cause bronchoconstriction and inflammation
Histamine and cysteine leukotrienes are predominant mast cell mediators.
What are the key cytokines released by T-helper 2 (Th2) lymphocytes?
- IL-4
- IL-5
- IL-13
IL-4 is essential for Ig-E development, IL-5 is an eosinophil growth factor, and IL-13 is associated with airway hyperresponsiveness.
What is the function of innate lymphoid cells (ILCs) in asthma?
They secrete Th2 cytokines and are induced by innate cytokines like IL-33
ILCs play a role in the initiation of allergic immune responses.
What is the relationship between neutrophils and asthma in children?
Neutrophils are not typically increased during stable disease but may rise during exacerbations
They may play a role in clearing infections rather than being pathogenic.
What are the structural airway changes associated with asthma?
- Increased thickness of the reticular basement membrane
- Increase in airway smooth muscle
- Increased number of vessels (angiogenesis)
These changes are present by school age, regardless of disease severity.
What is the significance of eosinophilic cationic protein (ECP) in asthma?
ECP is released by activated eosinophils but is not used to monitor disease
Its levels may correlate with peripheral blood eosinophils but not necessarily with airway eosinophilia.
What is exhaled nitric oxide (FeNO) used for in asthma diagnosis?
It is associated with airway eosinophilia and useful in supporting asthma diagnosis
FeNO levels can indicate adherence to inhaled steroid therapy.
What role does the pulmonary epithelium play in asthma?
It acts as an immunologically active barrier and is central to immune responses
Altered epithelial function is linked to asthma pathogenesis.
What cytokines are released by the airway epithelium in response to allergens?
- IL-33
- IL-25
- TSLP
These cytokines initiate immune responses in asthma.
What is T-cell plasticity in the context of asthma?
A change in the environment can alter the cytokine secretory pattern of T cells
This is crucial for maintaining the balance between regulatory and proinflammatory T-lymphocytes.
What cytokines are directly released in patients with asthma?
IL-33, IL-25, TSLP
These cytokines are influenced by environmental exposure and host susceptibility.
What is the role of airway epithelium in asthma?
Initiates immune responses without adaptive immunity
This occurs via antigen-presenting cells, allergen sensitization, and Ig-E production.
What do innate cytokines induce in asthma?
ILCs that function like T helper 2 cells
They secrete type 2 cytokines: IL-4, IL-5, IL-13.
What is the immunological role of airway smooth muscle in asthma?
Immunologically active component of airway wall
Interacts significantly with mast cells.
What is a significant predictor of asthma development from preschool wheeze?
Early alterations in smooth muscle function.
Define ‘Viral episodic wheeze’.
Wheezing in discrete episodes with no symptoms in between.
