Review Question - QID 100828

The vignette above most likely describes extrinsic asthma, due to a response generated by pet dander. Eosinophils play a key role during the late activation phase.

Type I hypersensitivity asthma results from a physiologic response to an inhaled (external) allergen which proceeds by specific stages: sensitization, early activation, and late activation. Late activation results in the activation of eosinophils which were recruited by eotaxin released during early activation.

Pollart et al. describe the new diagnosis and treatment guidelines for asthma. Treatment should be based on the severity at initial evaluation and control at all subsequent visits. Asthma severity is determined by current impairment and risk of future exacerbations.

Arron et al. describe the current understanding of asthma therapies as they relate to elevated levels of eosinophils, immunoglobulin E, and cytokines including interleukin (IL) 4, IL5, IL9, and IL13 and tumor necrosis factor (TNF). As response to treatment is highly heterogeneous, investigational therapeutics under clinical development for asthma include biologic therapies that specifically target mediators that may predominate in a given patient's presentation of asthma.

Figure A is a slide showing an eosinophil.

Illustration A depicts an electron micrograph (EM) of an eosinophil. Be able to identify various cell types by EM.

Incorrect Answers:
Answer 1: Sensitization is mediated by dendritic cells and Th2 CD4+ cells.
Answer 2: Early activation is mediated by mast cells.
Answer 4: Resolution is mediated by macrophages.
Answer 5: Remodeling is mediated by epithelial cells.