Allergen induced histamine release and immunoreactive-leukotriene C 4 generation from leukocytes in mite sensitive asthmatic patients

Abstract

Leukocytes from mite sensitive asthmatic patient were challenged with the allergen and the supernatant was assayed for histamine and immunoreactive-leukotriene C 4 (i-LTC 4). The release of histamine was quantitated by an automated fluorometric technique and i-LTC 4 was determined using a commercial radioimmunoassay kit. The results of analysis of the supernatant by high speed liquid chromatography, together with observations of modulation of the formation by agents, indicated that i-LTC 4 consisted of LTC 4 with a little amount of LTD 4. i-LTC 4 was generated as a result of basophil activation but not derived from the other cells such as monocytes and eosinophils. Allergen induced a concentration-dependent release of histamine and i-LTC 4 and the maximal release of histamine and i-LTC 4 occurred at the same dose of the allergen. At optimal concentration of the allergen, basophils produced 20.4 ± 17.9 ng of i-LTC 4/10 6-cells (mean ± S.D., n=39) and histamine release was 55.6 ± 20.1% of total histamine. There was a significant correlation in the capacity of leukocytes to release histamine and i-LTC 4 (r=0.47, p<0.01). We found a correlation between maximal histamine release or cell sensitivity, allergen concentration for 50% histamine release, and a ratio of specific IgE to mite to total IgE in the serum, but the amount of i-LTC 4 failed to correlate significantly with the ratio. The releasability and the cell sensitivity of asthmatic patients' cells to the allergen for histamine release paralleled the severity to symptoms, but this correlation was not significant in i-LTC 4 generation.