Effect of hypo- and hyper-osmolarity on basophil histamine release.

The pattern of histamine release from peripheral white blood cells in response to hyper-(sodium chloride, mannitol) and hypo-osmolar (water) stimuli was studied in order to determine the differences between non-atopic control and atopic asthmatic patients in histamine release caused by osmolar changes. All subjects showed histamine release to both hyper- and hypo-osmolar stimuli and this response was reproducible. Viability studies and the effect of time and temperature indicated that, at the extremes of hypo- and hyper-osmolality, histamine release was associated with cell cytotoxicity. Asthmatics and controls showed no differences either in their level of spontaneous or hyper-osmolar sodium chloride induced histamine release, but asthmatics' cells were more responsive to mannitol over 600-800 mOsm/kg and less responsive to a hypo-osmolar stimulus under 80 mOsm/kg. This suggests that asthmatics' cells may differ from controls in th manner in which they respond to osmotic stimuli and this may be relevant in certain clinical situations.