IgE+ plasmablasts predict the onset of clinical allergy

INTRODUCTION: IgE+ plasmablasts develop following allergen exposure and B cell activation. They secrete IgE and therefore are directly linked to maintain the mechanisms of IgE-mediated allergies. Here, we show that the presence of IgE+ plasmablasts in peripheral blood not only coincides with clinical allergy, but also predicts the upcoming development of clinical disease. METHODS: Using an equine model of naturally occurring allergy, we compared the timing of allergen exposure, arrival of IgE+ plasmablasts in peripheral blood, and onset of clinical disease. RESULTS: We found that IgE+ plasmablasts predict the development of clinical allergy by at least 3 weeks and can be measured directly by flow cytometry or by IgE secretion following in vitro culture. We also compared the IgE secretion by IgE+ plasmablasts with total plasma IgE concentrations and found that while IgE secretion consistently correlates with clinical allergy, total plasma IgE does not. DISCUSSION: Together, we describe IgE+ plasmablasts as a reliable and sensitive predictive biomarker of allergic disease development.