Evaluation of the potency of the allergen preparation Ambrosia elatior using a skin test and the inhibition radioallergosorbent test

: The total allergenicity of a pollen extract Ambrosia elatior was measured by quantitative prick test applied to the skin of seven highly sensitive patients and by standardized method of RAST-inhibition. Five 10-fold dilutions of the allergen concentration together with histamine hydrochloride 1 mg/ml (H1) were used. The induced wheal diametres for each concentration in per cent of the patient's own histamine wheal, were calculated. There was highly significant correlation (r = 0.9951) between the intensity of IgE mediated skin reactions and the IgE binding molecules in whole pollen extract. The concentration which provides the wheal equivalent to those of H1, found by linear regression analyses, was 54.9 micrograms/ml) in order to inhibit radioallergosorbent test with a pooled serum from the same patients, containing specific IgE antibodies against relevant allergens. Relevant allergen was a disk-allergen W1 (Pharmacia Diagnostics, Uppsala) The quantity of inhibition was proportional with allergen concentration (r = 0.9813). The concentration of 55.9 micrograms/ml, by linear regression analyses elicits inhibition of 50 per cent in RAST. It is concluded that quantitative prick test and histamine estimated skin sensitivity have a good clinical applicability in assessment of releaseability of skin mast cells, and together with RAST inhibition, provides the precise combined method for calibration of an allergenic extract potency.