Characterisation of textile dust extracts: I. Histamine release in vitro.

Cotton, flax, hemp, and cotton bracts extracts did not release histamine from mouse, rat, guinea pig, horse, cow, and monkey lung. Neither rat peritoneal mast cells nor mouse mastocytoma cells released histamine when incubated with textile dust extracts. Compound 48/80 caused a considerable release of histamine from all these tissues and the extracts released histamine from pig and human lung tissues. Whereas dusts that cause bronchospasm in man released histamine--for instance, cotton--those that are inactive, such as pericarps, did not. Histamine release was not quantitatively related to the concentration of extract used. Cotton bracts extract released histamine from pig lung tissue whereas in the same preparations methyl piperonylate was inactive. The active releasing agent was highly water soluble but could not be steam distilled from, nor extracted by, ether from bracts extract. These physicochemical properties are not characteristic of methyl piperonylate. There was no correlation between the induction of histidine decarboxylase and the histamine releasing capacity of the extracts. We conclude that pig lung is a useful qualitative assay tissue for the further characterisation of the histamine releasing agent(s) in textile dust extracts.