A linear correlation between histamine release and degranulation of human basophils by specific antigen or the ionophore A23187.

Simultaneous kinetic measurements have been made of basophil degranulation and of histamine release. Both antigen and ionophore A23187 were studied. Cells from the same donor under the same conditions undergo both reactions at a similar rate. Regression analysis indicated a statistically highly significant correlation between these two parameters for activation by either antigen or ionophore. In addition, the mean slope of the regression lines approached unity indicating a close direct correspondence between the number of cells degranulated and the quantity of histamine released. At any time during histamine release almost all of the cells identifiable as basophils were confluently stained and only rarely were partly degranulated cells observed. These results suggest that: (1) histamine release is not synchronous for populations of basophils; (2) individual cells are fully activated to begin histamine release at different times during the release period and then release all or almost all of their histamine in a short time relative to the total release period; (3) some cells release essentially none of their histamine and the number of these cells varies among donors and experimental conditions accounting in large measure for the incompleteness of histamine release.