Blood histamine level and histamine content in the lung tissue in immediate immunological reactions in human and experimental animals

The blood histamine level was determined in 66 patients with bronchial asthma and 25 guinea-pigs in whom the asthma attacks were induced by histamine or ovoalbumin inhalation after previous immunization of the animals. At the same time, histamine content of the lung tissue of the guinea-pigs was determined. It was found that in both humans and animals the level of blood histamine during immediate allergic reactions rises significantly. The extent of this rise depends on intensity of the reaction and time of determination. In asymptomatic period the blood histamine level did not differ from that of the control groups. Histamine concentration in the lung tissue of many of the animals increased during asthma attack but not in all cases was this increase correlated to the rise in blood histamine level. The reasons for these changes are discussed.