A child presents with chronic respiratory tract infections. All of the child's serum immunoglobulin levels are normal. Which genetic defect below might best explain these observations?

Question

Quizplus · Accepted Answer

B) Genetic deficiency of the secretory piece of IgA would best explain these observations because IgA is crucial for mucosal immunity, including protection of the respiratory tract. A deficiency in the secretory component would impair IgA's ability to be transported across epithelial surfaces, leading to increased susceptibility to respiratory infections despite normal serum immunoglobulin levels.

A Child Presents with Chronic Respiratory Tract Infections