AIM:To evaluate the mechanism of which brimonidine tartrate 0.15%causes clinical hypersensitivity.METHODS:A prospective case-control study comparing 8 glaucoma patients with clinical hypersensitivity to brimonidine to...AIM:To evaluate the mechanism of which brimonidine tartrate 0.15%causes clinical hypersensitivity.METHODS:A prospective case-control study comparing 8 glaucoma patients with clinical hypersensitivity to brimonidine to a control group consisting 13 healthy volunteers.Blood samples were stimulated with brimonidine 0.15%,timolol 0.5%or brimonidine tartrate/timolol maleate 0.2%/0.5%.Premixed antibodies(CD63/FITC and aIgE/PE)were added for direct staining and whole-blood samples were lysed,fixed and analyzed by a flow cytometer.The basophil population was defined by high IgE cell expression.Degranulation was identified by the expression of the activation molecule CD63.RESULTS:Basophil activation was not significant when comparing percent of activated basophils of patients and healthy controls after exposure to brimonidine(2.58%,2.45%,respectively,P=0.72).There was a significant suppression of basophil activation when a combination of brimonidine-timolol(0.87%)was compared to timolol(2.27%;P=0.012)and to brimonidine alone(2.58%;P=0.017).CONCLUSION:The results of our study do not support the hypothesis that brimonidine induces an immediate allergic reaction.Basophil activation was suppressed by the presence ofβ-blockers in patients hypersensitive to brimonidine and in healthy individuals.This finding indicates that timolol suppress brimonidine drug reaction by a different mechanism.展开更多
文摘AIM:To evaluate the mechanism of which brimonidine tartrate 0.15%causes clinical hypersensitivity.METHODS:A prospective case-control study comparing 8 glaucoma patients with clinical hypersensitivity to brimonidine to a control group consisting 13 healthy volunteers.Blood samples were stimulated with brimonidine 0.15%,timolol 0.5%or brimonidine tartrate/timolol maleate 0.2%/0.5%.Premixed antibodies(CD63/FITC and aIgE/PE)were added for direct staining and whole-blood samples were lysed,fixed and analyzed by a flow cytometer.The basophil population was defined by high IgE cell expression.Degranulation was identified by the expression of the activation molecule CD63.RESULTS:Basophil activation was not significant when comparing percent of activated basophils of patients and healthy controls after exposure to brimonidine(2.58%,2.45%,respectively,P=0.72).There was a significant suppression of basophil activation when a combination of brimonidine-timolol(0.87%)was compared to timolol(2.27%;P=0.012)and to brimonidine alone(2.58%;P=0.017).CONCLUSION:The results of our study do not support the hypothesis that brimonidine induces an immediate allergic reaction.Basophil activation was suppressed by the presence ofβ-blockers in patients hypersensitive to brimonidine and in healthy individuals.This finding indicates that timolol suppress brimonidine drug reaction by a different mechanism.
