Determinants of in vivo histamine release in cutaneous allergic reactions in humans

To determine host factors influencing the magnitude of mediator release during ongoing cutaneous allergic reactions in humans, we compared, in 22 subjects, the first-hour, second- to fifth-hour, and total (0 to 5 hours) skin chamber histamine release to (1) the in vitro reactivity and sensitivity of basophils to antigen for histamine release and (2) skin test sensitivity and reactivity to antigen, histamine, and codeine. There was no significant correlation between the first-hour and second- to fifth-hour histamine release. With a combination of basophil, antigen, histamine, and codeine skin sensitivity and reactivity, 64% to 75% of the magnitude of the first-hour, second- to fifth-hour, and total (0 to 5 hours) skin chamber histamine release could be accounted for. We conclude that antigen-induced in vivo allergic responses are a complex phenomenon dependent, in part, on antigen sensitivity, basophil and mast cell reactivity, and end organ responsiveness to mediators.