Analysis of environmental histamine from agricultural dust.

The agricultural worker can often be exposed to dust containing a complex mixture of organic materials. A variety of respiratory syndromes, including asthma, rhinitis, hyper sensitivity pneumonitis, and reactive and chronic obstructive airway disease, has been associated with acute and/or chronic agricultural dust exposures. Dose-response relationships have not been established for any of the respiratory conditions and select dust etiologic agents. This lack of established association is probably due to the multiplicity of biologically active agents found in the agricultural environment. An analysis of substances or organisms that may modulate the response to the primary etiologic agent could possibly aid the understanding of the clinical sequelae that follow exposure to high levels of organic dusts. Previous work in this laboratory has identified the presence of histamine in hay samples (1). Histamine is known as a potent vasodilator, bronchoconstrictor, and immunomodulator. The role of histamine in organic dust-induced disease is not known. It has the potential to cause, or contribute to, a primary response, as well as to modulate the response due to other agents such as endotoxin. A methodology to quantitate histamine levels from environmental air and bulk samples has been developed in our laboratory. The assay is applicable to the monitoring of histamine exposure in the workplace.