Ms. Debruinweller et al., ALLERGEN-INDUCED CHANGES IN AIRWAY RESPONSIVENESS ARE RELATED TO BASE-LINE AIRWAY RESPONSIVENESS, Allergy, 51(6), 1996, pp. 401-406
In the literature, bronchial allergen challenge is usually reported to
result in an increase in histamine-induced airway responsiveness (AR)
. The present study investigated the relation between baseline AR and
allergen-induced changes in AR. The effect of allergen challenge on AR
was investigated in 21 atopic asthmatic patients. Allergen challenge
resulted in a significant decrease in PC20 histamine after 24 h. When
the group was divided into three subgroups according to baseline PC20
histamine, a significant decrease in PC20 histamine was found only in
patients with relatively high baseline PC20 histamine (groups 1 and 2)
. A significant inverse correlation was found between baseline PC20 an
d allergen-induced PC20 histamine. The effect of repeated allergen cha
llenge on AR was studied in eight patients. The first allergen challen
ge resulted in a significant decrease in PC20 histamine; no further de
crease in mean PC20 histamine was seen after the second allergen chall
enge. These results suggest that allergen-induced changes in AR occur
mainly in patients with relatively high baseline PC20 values. Once an
increase in AR is induced, further allergen challenge does not always
result in further increase in AR.