Variations in chemical mediators of hypersensitivity in the sputum of chronic bronchitics: correlation with peak expiratory flow.

Histamine, slow reacting substance of anaphylaxis (S.R.S.-A), IgE, eosinophils, and an eosinophil-associated enzyme, arylsulphatase IIB, were measured in sputum from 11 chronic bronchitics at weekly intervals for 6 weeks. The agents were detected in all patients at some time and in the majority at all times throughout the study period although their concentrations varied. The variations in histamine, S.R.S.-A and IgE gave a highly significant negative correlation with the peak expiratory flow-rate, suggesting that chemical mediators of hypersensitivity may play some role in the pathogenesis of airways obstruction in this disease. Sputum eosinophilia correlated with the arylsulphatase IIB concentration but not with the peak expiratory flow-rate, IgE, histamine, or S.R.S.-A, a finding consistent with the view that eosinophils accumulate at the site of type I reactions after the peak of mediator release.