Lyons SA, Datema MR, Le TM, et al. - This study was intended to distinguish geographical variations in walnut component sensitization across Europe, explore cosensitization and cross-reactivity, and evaluate relationships of clinical and serological determinants with the severity of the walnut allergy. Researchers performed standardized clinical evaluation in 531 individuals reporting symptoms to walnut, with sensitization to all known walnut components assessed in 202 subjects, as part of the EuroPrevall outpatient surveys in 12 European cities. They applied Multivariable Lasso regression to evaluate predictors for walnut allergy severity. In Europe, Walnut-allergic individuals display clear geographical variations in walnut component sensitization and cosensitization patterns. This study's findings demonstrate that a predictive model combining outcomes from component-based serology testing with results from extract-based testing and information on clinical background permits for good discrimination between mild to moderate and severe walnut allergy.