Quantitative Inhalational Challenge Test

Abstract

Eighteen asthmatic patients were tested with antigens of house dust, mold, tree, grass and ragweed by the Anderson Sampler at National Jewish Hospital, Denver, Colorado.
(1) Anderson Sampler: This apparatus is devised to measure the exact quantity of an antigen inhaled and retained by the subject during an inhalational challenge test. It consists of nebulizer on the right which is connected by a series of tubes to an Anderson Sampler on the left. A known quantity of an antigen is mixed in the nebulizer with a known quantity of phenol red, used as a tracer dye, and 2 1/2% glycerol used to reduce vapor pressure and thus stabilize particle size. The material is then nebulized at a constant rate for five minutes.
At the end of this period, the optical density of the material in the sampler is carefully washed with a known amount of 0.05 normal sodium hydroxide solution and measured using a spectrophotometer.
In the third run, exactly the same procedure is repeated with only one difference; this time the patient is connected to the apparatus in such a way that while the nebulizer is running, he inhales from it for exactly five minutes. At the end of that period, material collected in the Anderson Sampler is measured again. This time, as expected, the optical density of the material collected in the sampler would be less than that in the original run. The amount which is lost has been obviously retained by the patient. No red dye is found in the mouth or the throat of the subject.
(2) The results are as follows:
1. Nine patients had a decreased FEV₁ between 26-60%, from 7-90 PNU of house dust. One of these had a shock reaction from 31 PNU of the house dust.
2. Seven patients showed a positive reaction from 16-263 PNU of mold and a decreased FEV₁ of 24-68%. One of these had a shock reaction from 59 PNU.
3. Five patients had a positive reaction from 23-251 PNU of tree antigen, however, no one fell in to shock.
4. From the grasses antigen, ten patients showed a positive reaction with 15-310 PNU; and decreased FEV₁. of 20-78%.
5. Ten patients had a reaction from 12-252 PNU of ragweed antigen and decreased FEV₁of 18-81%. Two of these had a shock reaction from 101 PNU and 142 PNU.
When we compared each allergen,50-55% of 18 patients showed a positive reaction to house dust, ragweed, grass, while 28-39 % of patients showed a positive reaction to mold and tree.
Looking at these reaction, we can see that the positve reaction to the tree allergen is weak, while the positive reaction to the ragweed allergen is strong.
With house dust, a positive reaction occured in all patients to a relatively small amount of allergen.
From our testing, we have determined that the house dust and ragweed allergens are the most significant to allergic asthma, and that there is no definite relationship between the amount of allergen and the degree of asthmatic reaction. Therefore the difference in degree of bronchial asthma depends on the bronchial sensitivity to particular antigens.