Activation of blood coagulation during inhalation challenge tests

Bronchial challenge tests were performed in 16 asthmatic subjects. Eight developed an immediate and eight a dual asthmatic response. In all patients serial blood samples were analysed for plasma recalcification time and Factor XII activation rate. In all instances a profound shortening of the recalcification time was found, but only in patients with a dual response could an increased activation rate of Factor XII be detected. A positive correlation, although weak, was found between the time of maximum shortening of recalcification time and the time of onset of the late reaction. The study suggests a relationship between activation of blood coagulation factors and the type of asthmatic response elicited after challenge test.