IGE-MEDIATED BASOPHIL RELEASABILITY IS INFLUENCED BY INTRINSIC-FACTORS AND BY IGE ON THE CELL-SURFACE

Experiments were done to clarify the mechanisms associated with releas ability of histamine. First, washed leukocytes from 23 asthmatic patie nts sensitive to mite allergen were challenged with Der p 1, a major a llergen isolated from Dermatophagoides pteronyssinus, or anti-IgE. A s ignificant correlation was observed between the ratio of Der p 1-speci fic IgE titer to total IgE level (S/T) in the patient's plasma and eit her the reactivity (maximal percentage of histamine release; r(s) = 0. 514, P = 0.016, n = 23) or the sensitivity (the minimum allergen conce ntration required to achieve 25% histamine release; r(s) = -0.790, P = 0.0002) to Der p 1. Additionally, the reactivity to Der p 1 was signi ficantly correlated with that to anti-IgE (r(s) = 0.690, P = 0.0012), indicating that an intrinsic cellular property may be one of the contr ibuting factors in immunologic histamine release. In a second series o f experiments, sinus mast cells were passively sensitized with immunog lobulins prepared from the patient's plasma. A statistically significa nt correlation was found between either the reactivity or the sensitiv ity to Der p 1 and S/T, thus indicating that S/T is an indicator of th e releasability of histamine. When basophils or mast cells were passiv ely sensitized with mouse IgE and subsequently stimulated with antimou se IgE, the reactivity to antihuman IgE was significantly correlated w ith that to antimouse IgE (r(s) = 0.966, P = 0.0023, n = 11). These ob servations suggest that an intrinsic cellular property regulates react ivity in immunologic histamine release. Taken together, our results su ggest that an intrinsic cellular property, as well as specific IgE ant ibody levels on the cell surface, is an important factor in determinin g histamine release in response to IgE-dependent activation.