PERIPHERAL-BLOOD EOSINOPHILIA IN INFANTS AT 3 MONTHS OF AGE IS ASSOCIATED WITH SUBSEQUENT DEVELOPMENT OF ATOPIC DISEASE IN EARLY-CHILDHOOD

Background: We tested the hypothesis that eosinophilia in peripheral b lood and nasal mucosa of infants is an early sign of allergic disease. Methods. The appearance of eosinophilic leukocytes in peripheral bloo d and nasal mucosa was studied prospectively in 67 infants up to 18 mo nths of age, with or without a family history of atopy. Results: eosin ophilia was associated with simultaneous presence or subsequent develo pment of atopic disease at 3, 9, and 18 months of age, but not signifi cantly so at 6 months. At 3 months children in whom atopic disease dev eloped later during the observation period had significantly higher nu mbers of blood eosinophils than children without atopy (p < 0.01). Thu s pronounced eosinophilia (> 7 x 10(8) cells/L) at that age was associ ated with moderate or severe allergic disease during the 18-month obse rvation period. These children continued to have eosinophilia througho ut the follow-up period. Blood eosinophilia at 3 months of age also co rrelated significantly to cord blood IgE levels and to skin prick test reactivity later during the follow-up period. Nasal eosinophilia was a common finding and therefore had little diagnostic or predictive val ue. Conclusions: Elevated eosinophil counts in peripheral blood of app arently healthy infants at 3 months of age is associated with a subseq uent diagnosis of atopic disease.