| Abstract: | Basophil releasability implies that, in addition to the surface density of IgE molecules, biochemical events determine the capacity to release chemical mediators in response to activating stimuli. We studied the IgE (anti-IgE)-mediated and non-IgE-mediated (f-met peptide and the Ca2+ ionophore A23187) releasability of human basophils obtained from 14 monozygotic (MZ) (ages 25.7 +/- 13.3 yr; mean +/- SDM) and 13 dizygotic (DZ) twin pairs (ages 20.4 +/- 9.9 yr). A significant intrapair correlation coefficient of the maximal percent of anti-IgE-induced histamine release was found in the MZ, whereas no significant correlation was found in the DZ. The mean intrapair variance of anti-IgE-induced histamine release in MZ (VMZ) and in DZ (VDZ) gave an F value equal to 3.84 (p less than 0.01) and a heritability (H) index of 0.74. Similar findings were obtained with respect to the sensitivity to a standard concentration (10(-1) micrograms/ml) of anti-IgE. No correlation between serum IgE level and anti-IgE-induced histamine release was found in either MZ or DZ. A significant intrapair correlation coefficient of f-met peptide-induced histamine release was found in both the MZ and the DZ. The difference between MZ and DZ was not significant. The VMZ and the VDZ of the f-met peptide-induced histamine release gave an F value of 1.52 (NS) and an H value of 0.34. The intrapair correlation coefficient of A23187-induced release was significant in MZ and not significant in DZ. The mean intrapair variance of A23187-induced histamine release gave an F value of 2.33 (NS) and an H index of 0.57. Similar findings were obtained by using suboptimal (3 X 10(-1) micrograms/ml) concentrations of A23187. There was no correlation between the sensitivity of basophils to release in response to anti-IgE and their response to f-met peptide or A23187, in either the MZ or the DZ. We conclude that the ability of basophils to respond to anti-IgE and A23187 is influenced by genetic factors. |
