Measurement of histamine-releasing factor activity in individual nasal washings: Relationship with atopy, basdphil response, and membrane-bound IgE

We collected individual pools of nasal washings (NWs) from 15 allergic and 15 nonallergic subjects to determine histamine-releasing factor (HRF) activity and to ascertain the relationship of these cytokines with atopic status, basophil releasability, and cell membrane-bound IgE. NWs were concentrated, dialyzed, and assayed with basophils from a single donor. Samples from 12 of 15 allergic subjects and from all the nonallergic subjects revealed {succeeds above single-line equals sign}15% histamine release (HR), 33.5% ± 21.3% (mean ± SD) and 38.6% ± 19.6%, respectively (p > 0.05). When we assayed the same samples with autologous basophils, the allergic group demonstrated higher HR than the nonallergic group (31.9% ± 19.7% versus 4.8% ± 4.3%; p < 0.001). A standard lot of mononuclear cell-derived HRFs was also screened with basophils from both groups. Means for HR from basophils of allergic and nonallergic subjects were 51.9% ± 16.7% versus 26.3% ± 8.2%, respectively (p < 0.001). Pretreatment of basophils with lactic acid led to abrogation of sensitivity to HRF. Acid-stripped cells incubated with sera from patients with asthma regained their capacity to release histamine. We found that HRF activity can be detected in NWs of most donors, and there is no difference among allergic and nonallergic subjects. Our results suggest that the capacity of these cytokines to induce HR depends on several factors: atopic status, basophil releasability, and membrane-bound IgE.