Relationships between Levels of Serum IgE, Cell-Bound IgE, and IgE-Receptors on Peripheral Blood Cells in a Pediatric Population

Background: Elevated serum immunoglobulin (Ig) E is a diagnostic marker of immediate-type allergic reactions. We hypothesize that serum IgE does not necessarily reflect total body IgE because in vivo IgE can be bound to cell surface receptors such as FcεRI and FcεRII (CD23). The aim of this study was to analyze the relationships between levels of serum IgE, cell-bound IgE, and IgE-receptors on peripheral blood cells in a pediatric population. Methodology: Whole blood samples from 48 children (26 boys, 22 girls, mean age 10,3±5,4 years) were analyzed by flow cytometry for FcεRI, CD23, and cell-bound IgE on dendritic cells (CD11c+MHC class II+), monocytes (CD14+), basophils (CD123+MHC class II-) and neutrophils (myeloperoxidase+). Total serum IgE was measured by ELISA and converted into z-units to account for age-dependent normal ranges. Correlations were calculated using Spearman rank correlation test. Principal Findings: Dendritic cells, monocytes, basophils, and neutrophils expressed the high affinity IgE-receptor FcεRI. Dendritic cells and monocytes also expressed the low affinity receptor CD23. The majority of IgE-receptor positive cells carried IgE on their surface. Expression of both IgE receptors was tightly correlated with cell-bound IgE. In general, cell-bound IgE on FcεRI+ cells correlated well with serum IgE. However, some patients carried high amounts of cell-bound IgE despite low total serum IgE levels. Conclusion/Significance: In pediatric patients, levels of age-adjusted serum IgE, cell-bound IgE, and FcεRI correlate. Even in the absence of elevated levels of serum IgE, cell-bound IgE can be detected on peripheral blood cells in a subgroup of patients

A parametric model for the changes in the complex valued conductivity of a lung during tidal breathing

Classical homogenization theory based on the Hashin-Shtrikman coated ellipsoids is used to model the changes in the complex valued conductivity (or admittivity) of a lung during tidal breathing. Here, the lung is modeled as a two-phase composite material where the alveolar air-filling corresponds to the inclusion phase. The theory predicts a linear relationship between the real and the imaginary parts of the change in the complex valued conductivity of a lung during tidal breathing, and where the loss cotangent of the change is approximately the same as of the effective background conductivity and hence easy to estimate. The theory is illustrated with numerical examples, as well as by using reconstructed Electrical Impedance Tomography (EIT) images based on clinical data from an ongoing study within the EU-funded CRADL project. The theory may be potentially useful for improving the imaging algorithms and clinical evaluations in connection with lung EIT for respiratory management and monitoring in neonatal intensive care units

CD-Sens Can Be a Reliable and Easy-to-Use Complement in the Diagnosis of Allergic Rhinitis

Background: A reproducible standard for a graded allergen response in allergic rhinitis is lacking. The aim was to evaluate basophil allergen threshold sensitivity, CD-sens, as a diagnostic complement to nasal allergen challenge. Methods: Twenty-six patients with a history of allergic rhinitis due to grass pollen were intranasally challenged and nasal symptom score and peak nasal inspiratory flow (PNIF) changes were determined after 15 min. A 20% decrease in PNIF or a symptom score >= 2 were considered a positive test. A blood sample for CD-sens was drawn before each challenge. Eighteen patients were tested twice. Results: CD-sens agreed with the positive or negative nasal symptom score in 22/26 and PNIF in 24/26 patients. After the second challenge, 14/18 patients had the same symptom, 17/18 the same PNIF, while all had identical CD-sens classification. Conclusion: CD-sens appears to be a reproducible test for diagnosis of allergic rhinitis with great advantages also for follow-up of disease development and treatment effects. Copyright (C) 2012 S. Karger AG, Base

Xolair Is Effective in Allergics with a Low Serum IgE Level.

Background: Two atopic patients suffering from severe allergy difficult to handle by conventional medication were given Xolair despite an IgE level <30 kU/l. Methods: Increasing dosages were given and monitored by clinical evaluation and CD-sens to clinically relevant allergens. The patients' IgE antibody fractions were 11-14%. Results: Xolair dosages extrapolated from a recommended dose for IgE of 30-75 kU/l were adapted to the patients' IgE body pool but had very little effect. The double dose resulted in some clinical improvement and a decrease in CD-sens. However, not until the dose was doubled again did the patients become symptom free, although 1 patient needed some additional drugs but no oral steroids. CD-sens turned negative to 5 of the 7 tested allergens. Conclusions: Xolair is most useful also in atopics with an IgE level <30 kU/l. The dose must be adjusted to the size of the IgE antibody fraction adding all non-cross-reacting, clinically relevant specificities