Early-life EBV infection protects against persistent IgE sensitization

BackgroundInfection with EBV has previously been implicated in influencing allergic disorders, but its precise role remains contradictory. The timing of primary infection may contribute to the discrepancies.ObjectiveThis study aimed at investigating whether the time-point of primary EBV infection during childhood could be of importance in modulating the risk of developing IgE sensitization.MethodsA total of 219 Swedish infants were followed prospectively to 5 years of age with clinical examinations, skin prick testing, specific IgE analyses, and determination of serostatus against EBV.ResultsAfter analysis of the children's EBV serostatus, we found that 5-year-olds who were infected with EBV before the age of 2 years were at a significantly lower risk of being persistently IgE-sensitized—that is, sensitized at both 2 and 5 years of age (adjusted odds ratio, 0.34; 95% CI, 0.12-0.94). In contrast, contraction of EBV after 2 years of age was highly associated with late-onset IgE sensitization (adjusted odds ratio, 4.64; 95% CI, 1.57-13.69). Persistently sensitized 5-year-olds had higher specific-IgE levels than children with late-onset IgE sensitization (P < .01).ConclusionOur data support the value of early-life microbial exposure for protection against the development of IgE sensitization and underscore the proximate postnatal years as an important period during which EBV could contribute to an allergo-protective immune profile.