Soluble FcɛRI: A biomarker for IgE‐mediated diseases

Abstract

Soluble IgE receptors interact with IgE in the extracellular matrix andare important in the regulation of immune diseases.1-5Soluble FcεRII(sCD23) and galectin‐3(εBP) are currently used as biomarkers,1though correlation data on serum titers and severity of allergies arecontroversial.1,6FcεRI, the high‐affinity IgE Fc receptor, is expressed on severalinnate cell types,2and a truncated version of the IgE‐binding alphasubunit is found as a soluble isoform (sFcεRI) in human serum. In cir-culation, sFcεRI is mostly detected as a complex with IgE.7Thisobservation raises the question of how sFcεRI affects detection ofserum IgE titers.In order to assign clinical implications of sFcεRI, we assessedserum titers in its total and IgE‐bound forms in different IgE‐mediated diseases in 312 individuals. We compared pediatric popula-tions with primary food allergies (n = 59), insect venom allergies(n = 9), allergic asthma (n = 24), atopic dermatitis (n = 25), food‐sen-sitized nonallergic children (n = 31), and nonallergic controls (n = 17).Additionally, other sensitized groups and controls (n = 147) wereincluded in the study (Table S1-S4).