Numerical changes in blood monocytes in bronchial asthma.

Numerical changes in peripheral blood monocytes were examined in 125 patients with bronchial asthma using a new direct method of counting blood monocytes. The number of monocytes in non-attack stages of bronchial asthma was similar to that of healthy controls. The monocyte count observed in overall cases showed a significantly higher value both in pre-attack and attack stages than in non-attack stages. Changes in the number of monocytes in an individual spontaneous asthmatic cycle tended to increase in pre-attack stages, increase more markedly during asthma attacks, then to decrease after the attack was alleviated. Monocytes in cases with a positive test for bronchial challenge to house dust extract changed in almost the same manner as for spontaneous asthma attacks. The number of monocytes did not change during bronchospasm provoked by inhalation of acetylcholine. Exercise-induced asthma patients exhibited indefinite changes of monocytes; that is, some cases showed a significant increase in the number of monocytes related to the asthma cycle, but other cases did not show any appreciable change. These findings suggest that the number of monocytes in the peripheral blood may change in close relation to asthma attacks elicited by allergic reactions.