Biomedical subjects
Publications and source records attributed to R Voorhorst.
Some formulas are given for the relationship between the sizes of wheals and flares of skin reactions to three allergen extracts and to histamine and compound 48/80. Only compound 48/80 shows a somewhat different wheal/flare relationship.
Using a perfected technique for skin testing, no difference was found between skin reactions to either histamine or compound 48/80 in atopic and non-atopic patients or in healthy volunteers. The correlation of the size of the skin reactions to both compounds was only slightly lower than the correlation of the duplicates, which indicates that compound 48/80 can be used as a control extract in skin testing. The skin reactions to this compound are read after 15 minutes, just as those to inhalant allergens.
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The use of an immunofluorescence method for demonstration of non-capsulated H. influenzae colonization and penetration in the tissues of the respiratory tract seems to be a useful and convenient laboratory method. However, in in the tissues of the lower respiratory tract H. influenzae in our materials could not be demonstrated.
Atopy to dander from domestic animals occurs rather frequently in atopic patients, especially danders from the cat, guinea-pig, horse, rabbit, and golden hamster. There is no clear sex difference. The age group in which the phenomenon is found most frequently is from 21 to 30 years. As in hay-fever patients during the season, we found a double-peaked frequency curve for the blood eosinophilia. Animal-dander atopy was diagnosed particularly in patients with asthma and/or with atopic eczema. The strength of skin reactions to a series of three tenfold dilutions of standardized test extracts appears to be a good index for the origin of clinical symptoms after contact with the relevant animals.
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Analysis of skin-test results obtained with compound 48/80 has indicated that this substance deserves a place in the standard series of test fluids for routine skin testing. No influence of sex or season was detected but there were significant differences in response related to the age (strongest reactions in the 16-40 year age group) and to the diagnosis (strongest reactions in the atopic patients).
Human dander is shown to be a true allergen giving skin reactions most frequently in atopic patients. The clinical importance of human dander is discussed and data of a group of patients atopic only to human dander are given. It seems probable that human dander is an auto allergen and that there are many more auto allergens to which the atopic organism produces IgE-type antibodies.
Besides describing some pitfalls frequently ignored in investigations on the house dust Dermatophagoides allergen problem, the author demonstrates that skin reactions due to the very small amount of "residual allergen activity" in house dust can be explained by the fact that house dust always contains a small percentage of human dander.
It is demonstrated that the sum of the length and width of the flare is linearly correlated with the logarithm of the sum of the length and width of the wheal; on this basis a valuable "skin-reaction index" is proposed. Furthermore, the log-dose response curve of the skin reaction, at least in the medium-sized reactions, proved to be a straight line. These methods permit a bio-assay of allergens extracts giving a maximal dispersion of 100% above and below the exact value. Coefficient of variation: 62%.
From the seemingly most appropriate methods for standardization procedures of allergen extracts, the most serious candidates are in sequence of age: the old atopic skin test, the histamine-release test, using human basophil cells and the radio-allergosorbent test. At the moment it is not yet certain which method gives the most exact results, although, especially in the last ones - as part of the whole test - highly sophisticated methods are used. The skin test is not dependent on modern laboratory methods, is used on a world-wide scale, but as method studied very poorly. This is a matter of regret, because at any rate the skin test gives the clinician a lot of valuable information. The major drawbacks of the skin test are that the inclination of the log-dose response line is rather small and that the results of tests done with the same dose may vary sometimes not inconsiderably. Furthermore, the results are dependent on the sites of the skin where the tests are done and on the amount of fluid injected intracutaneously. There is a diurnal variability, a certain influence of the menstrual cycle and of course influence of medicaments (histamines). Nevertheless, taking all these factors into consideration and using a highly perfected method of skin testing, it appeared possible in 16 experiments, with not more than six volunteers per experiment, to reduce the variability of the bioassay between the limits of +50 and minus 50 per cent.
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