Bronchus-associated lymphoid tissue in human lung: Correlation of hyperplasia with chronic pulmonary disease

Abstract Nine patients with chronic or recurrent pneumonia had as a principal abnormality the presence of lymphoid masses around the bronchi and bronchioles. Many small airways were obstructed or destroyed. We found that the lymphoid tissues had characteristics of bronchus-associated lymphoid tissue (BALT). While BALT performs an essential immunologic function in airways, hyperplasia of this structure may contribute to bronchial pathology.