What causes increased susceptibility to infections when vitamin A deficiency impairs mucociliary clearance in the respiratory tract?

💡 Explanation

Vitamin A is essential for epithelial cell differentiation; deficiency results in squamous metaplasia, which impairs mucociliary clearance because ciliated cells are replaced by keratinized cells. Therefore, impaired epithelial cell differentiation explains increased susceptibility to infection, rather than other immune cell dysfunctions or complement activation.

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