Histamine and leukotriene C4 release in cutaneous mosquito-bite reactions.
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.
Horsmanheimo
L
L
Department of Dermatology, Kuopio University Hospital, Finland.
Harvima
I T
IT
Harvima
R J
RJ
Brummer-Korvenkontio
H
H
François
G
G
Reunala
T
T
D000328:Adult; D000330:Aedes / Q000276:immunology*; D000818:Animals; D005260:Female; D006632:Histamine / Q000378:metabolism*; D006636:Histamine Release; D006801:Humans; D007299:Insect Bites and Stings / Q000276:immunology* / Q000378:metabolism*; D017997:Leukotriene C4 / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D008875:Middle Aged; D012867:Skin / Q000737:chemistry
D017997:Leukotriene C4; D006632:Histamine