Immunological aspects of asthma

Tracheal basement membrane thickening in rhesus monkeys

Thickened hyaline tracheal membrane similar to that which occurs with several respiratory conditions in man was seen in Rhesus monkeys. The membrane was eosinophilic and up to 50.4 μm thick. Frequently eosinophils and mast cells were seen in the tracheal mucosa and submucosa. Using fluorescent microscopy, IgG, B1C, B1A and albumin were identified in the membrane. Electron microscopy showed that the membrane was composed of 18.8-nm collagen-like fibrils with occasional periodicity. The cause of the thickened hyaline tracheal membrane could not be determined. The changes probably represent a response to mild repeated or continuous tracheal injury owing to a variety of causes. Delineation of the cause of this process in nonhuman primates may help in the understanding of respiratory diseases in man.