Which histologic feature indicates irreversible airway remodeling in chronic asthma?

The presence of an increased proportion of myofibroblasts is indicative of irreversible airway remodeling in chronic asthma. Myofibroblasts are specialized cells that play a crucial role in tissue repair and fibrosis. In the context of asthma, their proliferation leads to the deposition of extracellular matrix components, which can contribute to structural changes in the airways such as thickening and stiffening.

When the airway epithelium is damaged due to chronic inflammation, myofibroblasts migrate to the site as part of the healing process. However, in chronic asthma, their continued activation contributes to persistent remodeling, resulting in narrowed airways and impaired lung function. This remodeling can become irreversible, leading to long-term consequences for individuals with asthma.

Increased eosinophils, while associated with asthma inflammation, reflect the acute inflammatory response rather than chronic structural changes. Decreased smooth muscle mass would suggest a reduction in the muscle responsible for airway constriction, which is not consistent with the remodeling process seen in chronic asthma. Thickening of the epithelial layer is also a feature of ongoing inflammation rather than a definitive marker of irreversible remodeling on its own.