BACKGROUND: Mosquito bites are known to sensitize persons, and the most common cutaneous reactions are immediate wheals and delayed bite papules. Anti-saliva IgE and IgG4 antibodies are common in mosquito-sensitive subjects, but mediator release in bite reactions is not known. METHODS: We used the microdialysis technique to measure in vivo histamine and leukotriene C4 release after bite challenges in six mosquito-sensitive subjects. One individual who was not sensitive to bites volunteered as a control subject. RESULTS: Three of the six mosquito-sensitive subjects had large wheals and showed clearly increased histamine concentrations 30 to 45 minutes after the bites. The histamine levels declined to baseline value within 2 hours; thereafter, one subject showed a second increase in histamine concentration. Four of the six mosquito-sensitive subjects showed increased leukotriene C4 concentrations, and this mediator seemed to be released somewhat later than histamine. CONCLUSIONS: The increased histamine and leukotriene C4 release observed in this study suggests that both mediators are involved in the early allergic response caused by mosquito bites.
BACKGROUND: Mosquito bites are known to sensitize persons, and the most common cutaneous reactions are immediate wheals and delayed bite papules. Anti-saliva IgE and IgG4 antibodies are common in mosquito-sensitive subjects, but mediator release in bite reactions is not known. METHODS: We used the microdialysis technique to measure in vivo histamine and leukotriene C4 release after bite challenges in six mosquito-sensitive subjects. One individual who was not sensitive to bites volunteered as a control subject. RESULTS: Three of the six mosquito-sensitive subjects had large wheals and showed clearly increased histamine concentrations 30 to 45 minutes after the bites. The histamine levels declined to baseline value within 2 hours; thereafter, one subject showed a second increase in histamine concentration. Four of the six mosquito-sensitive subjects showed increased leukotriene C4 concentrations, and this mediator seemed to be released somewhat later than histamine. CONCLUSIONS: The increased histamine and leukotriene C4 release observed in this study suggests that both mediators are involved in the early allergic response caused by mosquito bites.