Organic dust diseases and endotoxins.

On the basis of available information it is not justifiable to conclude that endotoxins are responsible for extrinsic allergic alveolitis by biological activities that are associated with endotoxin properties per se. Endotoxin-like material has been found in materials associated with byssinosis, farmer's lung and sewage sludge disease and a case for their involvement in the aetiology of byssinosis and sewage sludge disease can be made out. However, endotoxin-like activity in farmer's lung is less important than the hypersensitivity reaction except possibly where heavy doses of mouldy hay dust are inhaled. The indirect role of endotoxin in promoting a hypersensitivity response, i.e. by adjuvant activity, etc., is undoubtedly more important than is its direct action in this disease.