Evidence for natural desensitization to mosquito salivary allergens: mosquito saliva specific IgE and IgG levels in children

Abstract

There are few epidemiologic data on the prevalence of mosquito allergy, although local reactions to mosquito bites are common. To investigate the prevalence of mosquito allergy in children by measuring serum levels of mosquito saliva specific IgE and IgG antibodies that correlate well with the size of mosquito bite local reactions. Using enzyme-linked immunosorbent assays to measure mosquito (Aedes vexans) saliva-specific antibodies, we investigated sensitization to mosquito bites in 402 children aged 1 month to 18 years and correlated mosquito saliva specific IgE and IgG levels with age and sex. Twenty-three serum samples from infants who had never been exposed to mosquitos were used as negative controls. Mean levels of mosquito saliva specific IgE and IgG were lowest in the 23 negative control serum samples. In the 402 samples from children who may have been exposed to mosquitos, mean saliva specific IgG levels were higher in boys than in girls (P < .008). Levels of IgE and IgG correlated with each other (P < .001). A significant inverse correlation was found between age and both IgE and IgG levels. IgE levels peaked at the age of 6 to 12 months of age, and IgG levels peaked at 1 to 6 months of age. Levels of IgE and IgG antibodies gradually declined after the age of 5 years. Based on the presence of mosquito saliva specific antibodies, exposed infants and young children are at increased risk of having allergic reactions to mosquito bites. Antibody levels decline throughout childhood and adolescence, suggesting that natural desensitization may occur.