Tracheobronchial amyloidosis: evidence for local B-cell clonal expansion: Figure 1–

Abstract

To the Editors: Amyloidosis is characterised by the deposition of insoluble protein fibrils in organs and tissues, which leads to organ dysfunction. Amyloidosis is classified according to the composition and localisation of fibrils. The most frequent amyloidosis is immunoglobulin (Ig)-light-chain (AL) amyloidosis. In systemic AL amyloidosis, the fibrils are derived from circulating monoclonal light chains that are usually produced by intramedullary clonal plasma cells. Localised AL amyloidosis is most often identified in upper respiratory, urogenital and gastrointestinal tracts, in the skin and in the orbit. In such circumstances, the amyloidogenic light chains are produced by a subtle clone of lymphoplasma cells localised near the amyloid deposits [1]. Characterising the associated clonal cells is often not possible because of their low number. Tracheobronchial amyloidosis is a rare form of localised amyloidosis [1,2]. To our knowledge, local B-cell clonal expansion has never been consistently demonstrated in tracheobronchial amyloidosis. We present the first case of tracheobronchial amyloidosis with molecular demonstration of localised tracheobronchial B-cell clonal proliferation and the results of targeted B-cell therapy with rituximab. A 41-yr-old female complained of persistent cough and expectoration for 1 yr. She was a 10-pack-yr active smoker. The physical examination was unremarkable. Lung function tests revealed an obstructive pattern, with a forced expiratory volume in 1 s of 1,880 mL (66%) and vital capacity of 3,420 mL (102%) without reversibility. Thorax computed tomography (CT) revealed a thickening of the trachea and primary bronchi without sparing the posterior tracheal wall (fig. 1a). Bronchoscopy confirmed a diffuse infiltration of the mucosa from the beginning of the trachea to the beginning of the tertiary bronchi, without sparing the …