Is airway hyperactivity in asthma due to histamine H2-receptor deficiency?

The underlying biochemical and physiological changes responsible for remarkable airway hyperreactivity to histamine and other non-specific stimuli in asthmatics are poorly understood. Based on some experimental observations, a hypothesis "Deficiency of histamine H2-receptors in asthma" is proposed. The deficiency of histamine H2-receptor (histamine-sensitive adenyl cyclase) on leukocytes (mast cells, basophils, neutrophils and eosinophils) and in the airway smooth muscles during the process of hypersensitization, immunization, infectious diseases as well as in atopic bronchial asthmatics could occur. The H2-receptor deficiency or physiological imbalance of histamine H1- and H2-receptors in the airways may at least, in part, explain the most commonly observed phenomenon of remarkable airway hyperreactivity to histamine in asthmatics.