| Abstract: | Circulating human basophils contain histamine, a potent mediator of inflammation. Previous in vitro studies have shown that histamine 'releasability' in asthmatic subjects differs from normal subjects but have not evaluated possible differences in the immunopharmacological control of the release of this mediator which might account for these differences. The purpose of the present study was to examine the immunopharmacologic control of basophil histamine release in 14 asthmatics and 10 normal subjects who were characterized by pulmonary function tests, allergic status (skin tests and serum IgE levels) and nonspecific airways reactivity to methacholine and histamine. Basophils were stimulated with anti-IgE, and the inhibitory effects of the H2 agonist, dimaprit, and dibutyryl cyclic AMP (dbcAMP), as well as the enhancing properties of 5-hydroperoxyeicosatetraenoic acid (5-HPETE) and indomethacin on the modulation of histamine release, were investigated. Although no statistically significant differences were seen in the percent histamine release triggered by anti-IgE in these two groups, enhancement of histamine release by 5-HPETE was more consistent in the asthmatic subjects (10 of 10) than in control subjects (6 of 8). The percent increase in histamine release produced by 5-HPETE in asthmatic subjects averaged 3.9 +/- 1.3% using 0.03 micrograms anti-IgE/ml and 4.8 +/- 3.2% using 0.1 microgram anti-IgE/ml (p less than 0.002, Wilcoxon's signed rank test), and averaged 3.0 +/- 4.3 and 3.1 +/- 5.3%, respectively, in control subjects (p greater than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS) |
