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Background Previous studies of serum total IgE (t-IgE) were not able to discriminate well-enough atopic from non-atopic subjects, that is, with or without serum-specific IgE antibodies to allergens. Objectives To model growth curves of the total IgE levels in children without atopic sensitization (hereafter defined as 'normal' t-IgE levels) and to test their usefulness in predicting atopic sensitization. Methods The German Multicentre Allergy Study ( MAS), a birth cohort with 1314 recruited newborns, began in 1990 and examined the participants until age 20 years. Total and specific IgE (t-IgE, s-IgE) were analyzed with a fluorescent enzyme immunoassay Immuno CAP ( TFS, Sweden) at ages 1, 2, 3, 5, 6, 7, 10, 13, and 20 years. Participants were classified as 'never atopic' if all their available serum samples had negative response (cutoff: <0.35 kUA/L) for s-IgE to the nine common foodborne and airborne allergenic extracts (milk, egg, soy, wheat, house dust mite, cat, dog, birch, and grass) tested in the MAS birth cohort. By contrast, participants were defined as atopic if they had, for at least at one available serum sample, s-IgE≥0.35 kUA/L to at least one allergenic extract tested. The evolution of t-IgE levels in the 'never atopic' children was described by growth curves, estimated by exploiting a quantile regression model. A 'reference' percentile, based on the t-IgE value measured at age 5 years, was assigned to each child with no IgE sensitization at that age. Upward deviations from the own 'reference' quantile of t-IgE in atopic and 'never atopic' children were calculated and a ROC analysis was used to identify the best cutoff point for predicting atopic sensitization. Results Overall, 1113 of 1314 children were included in this analysis. Of these, 469 were 'never atopic' and 644 atopic. Quantile trajectories of t-IgE levels in 'never atopic' subjects were stable from 5 years of age, increased to a plateau at age 10-13 years, and decreased slightly afterward. The onset of atopic s-IgE responses was characterized by an upward deviation of serum t-IgE levels from their 'reference' trajectory. T-IgE quantiles predicted the onset of atopy with high efficiency ( AUC>80%). ROC analysis showed that deviations from the t-IgE level 'reference' quantile above 0.32, 0.41, 0.42, 0.30, and 0.58 kU/L (log-units) at 6, 7, 10, 13, and 20 years of age, respectively, predicted an atopic sensitization. Conclusion The growth curves of 'normal' serum t-IgE concentrations were estimated in 'never atopic' children; for each individual who was non-atopic at 5 years of age a 'reference' quantile was identified that represented the individual's 'normal' level of t-IgE production. Upward deviations of observed t-IgE levels from the own 'reference' quantile, from 6 to 20 years of age, predicted at each year the occurrence of atopic sensitization. Clinical Implications The trajectory of t-IgE levels can be elaborated since age 5 years in non-atopic children. A child whose t-IgE levels are consistently higher than those predicted by his/her growth curve may have developed atopic sensitization. [ABSTRACT FROM AUTHOR]

Background The evolution of the IgE response to the numerous allergen molecules of Dermatophagoides pteronyssinus is still unknown. Objectives We sought to characterize the evolutionary patterns of the IgE response to 12 molecules of D pteronyssinus from birth to adulthood and to investigate their determinants and clinical relevance. Methods We investigated the clinical data and sera of 722 participants in the German Multicenter Allergy Study, a birth cohort started in 1990. Diagnoses of current allergic rhinitis (AR) related to mite allergy and asthma were based on yearly interviews at the ages of 1 to 13 years and 20 years. IgE to the extract and 12 molecules of D pteronyssinus were tested by means of ImmunoCAP and microarray technology, respectively, in sera collected at ages 1, 2, 3, 5, 6, 7, 10, 13, and 20 years. Exposure to mites at age 6 and 18 months was assessed by measuring Der p 1 weight/weight concentration in house dust. Results One hundred ninety-one (26.5%) of 722 participants ever had IgE to D pteronyssinus extract (≥0.35 kU A /L). At age 20 years, their IgE recognized most frequently Der p 2, Der p 1, and Der p 23 (group A molecules; prevalence, >40%), followed by Der p 5, Der p 7, Der p 4, and Der p 21 (group B molecules; prevalence, 15% to 30%) and Der p 11, Der p 18, clone 16, Der p 14, and Der p 15 (group C molecules; prevalence, <10%). IgE sensitization started almost invariably with group A molecules and expanded sequentially first to group B and finally to group C molecules. Early IgE sensitization onset, parental hay fever, and higher exposure to mites were associated with a broader polymolecular IgE sensitization pattern. Participants reaching the broadest IgE sensitization stage (ie, ABC) had significantly higher risk of mite-related AR and asthma than unsensitized participants. IgE to Der p 1 or Der p 23 at age 5 years or less predicted asthma at school age. Conclusions Parental hay fever and early exposure to D pteronyssinus allergens promote IgE polysensitization to several D pteronyssinus molecules, which in turn predicts current mite-related AR and current/future asthma. These results might inspire predictive algorithms and prevention strategies against the progression of IgE sensitization to mites toward AR and asthma. [ABSTRACT FROM AUTHOR]

Background: IgE sensitization against grass pollen is a cause of seasonal allergic rhinitis. Objective: We sought to investigate the evolution at the molecular level and the preclinical predictive value of IgE responses against grass pollen. Methods: The German Multicentre Allergy Study examined a birth cohort born in 1990. A questionnaire was administered yearly, and blood samples were collected at 1, 2, 3, 5, 6, 7, 10, and 13 years of age. Grass pollen–related seasonal allergic rhinitis (SARg) was diagnosed according to nasal symptoms in June/July. Serum IgE antibodies to Phleum pratense extract and 8 P pratense molecules were tested with immune-enzymatic singleplex and multiplex assays, respectively. Results: One hundred seventy-seven of the 820 examined children had SARg. A weak monomolecular/oligomolecular IgE response to P pratense was observed very frequently before SARg onset. These initial IgE responses increased in concentration and molecular complexity during the preclinical and clinical process. A typical progression of IgE sensitization was observed: Phl p 1 (initiator in >75% of cases); then Phl p 4 and Phl p 5; then Phl p 2, Phl p 6, and Phl p 11; and then Phl p 12 and Phl p 7. At age 3 years, IgE sensitization predicted SARg by age 12 years (positive predictive value, 68% [95% CI, 50% to 82%]; negative predictive value, 84% [95% CI, 80% to 87%]). At this preclinical prediction time, the number of recognized molecules and the serum levels of IgE to P pratense were significantly lower than at 3 or more years after SARg onset. Conclusions: The IgE response against grass pollen molecules can start years before disease onset as a weak monosensitization or oligosensitization phenomenon. It can increase in serum concentration and complexity through a “molecular spreading” process during preclinical and early clinical disease stages. Testing IgE sensitization at a preclinical stage facilitates prediction of seasonal allergic rhinitis at its molecular monosensitization or oligosensitization stage. [Copyright &y& Elsevier]