A 23-year-old man comes to the physician because of a 1-year history of episodic shortness of breath. Physical examination shows no abnormalities. Laboratory studies show elevated serum IgE levels. Microscopic examination of the sputum shows eosinophilic, hexagonal, double-pointed crystals. Physical examination reveals scattered expiratory wheezes in both lungs. Peak expiratory flow rate is decreased from baseline. The treatment regimen is expanded to include a monoclonal antibody that binds circulating IgE, with the resulting complexes being subsequently cleared by reticuloendothelial cells. This medication is most likely to help this patient through which of the following mechanisms?

Question

A 23-year-old man comes to the physician because of a 1-year history of episodic shortness of breath. Physical examination shows no abnormalities. Laboratory studies show elevated serum IgE levels. Microscopic examination of the sputum shows eosinophilic, hexagonal, double-pointed crystals. Physical examination reveals scattered expiratory wheezes in both lungs.  Peak expiratory flow rate is decreased from baseline. The treatment regimen is expanded to include a monoclonal antibody that binds circulating IgE, with the resulting complexes being subsequently cleared by reticuloendothelial cells.  This medication is most likely to help this patient through which of the following mechanisms?

Quizplus · Accepted Answer

Eductional Objective: Allergic asthma is caused by the binding of allergen-specific IgE to high-affinity receptors on basophils and mast cells. By binding circulating IgE, omalizumab reduces the serum levels of free IgE, which reduces the stimulation of mast cells and basophils and prevents activation of the inflammatory cascade. Over time, reduced serum IgE levels result in downregulation of FcRI on these cells.

A 23-Year-Old Man Comes to the Physician Because of a 1-Year