Role of serum-specific immunoglobulin E in egg allergy: a comprehensive study of Portuguese pediatric patients.

INTRODUCTION: Food allergies represent a growing public health concern, particularly among children. This study aims to examine egg allergy in pediatric patients and analyze the value of serum-specific immunoglobulin E (sIgE) levels as predictive biomarkers for oral food challenge (OFC) outcomes. METHODS: Retrospective study, involving pediatric patients with suspected IgE-mediated egg allergy, conducted at a tertiary hospital. RESULTS: Data from 176 pediatric patients were analyzed, revealing a higher male prevalence (59.1%). Most cases (40.3%) presented symptoms in the first year of life, predominantly mucocutaneous symptoms (46%). OFC results varied across various forms of egg presentation, with cooked egg being the most frequently tested food. Positive OFCs were observed in 14.6% (n = 36) of cases. The study identified specific egg protein biomarkers for positive OFC, with ovalbumin for raw egg (sIgE > 1.28 KUA/L; area under the curve [AUC] = 0.917; sensitivity [S] 100%; and specificity [Sp] 92%), ovomucoid for cooked egg (sIgE > 0.99 KUA/L; AUC = 0.788, 95%; S: 79%; and Sp: 74%), and ovomucoid for baked egg (sIgE> 4.63 KUA/L; AUC = 0.870; S: 80%; and Sp: 85%) showing predictive capacities. CONCLUSIONS: The findings underscore the importance of considering various forms of egg presentation in the diagnosis and management of egg allergy. The findings highlight the valuable discriminatory capacity and provided reliable biomarkers, such as ovalbumin for raw egg and ovomucoid for cooked and baked egg in risk assessment, aiding in predicting OFC outcomes and helping clinicians to make informed decisions in diagnosing and managing egg allergies, thus improving patient care and quality of life.

Recurrent pyogenic infections caused by a novel Gln1420* mutation in the C3 gene.

C3 is a crucial protein of the complement system. Congenital C3 deficiency is extremely rare and manifests through recurrent, severe infections and should always be considered as a differential diagnosis of recurrent pyogenic infections. We report a case of a patient with a novel C3 gene mutation, responsible for complete C3 deficiency with impaired complement system activation and recurrent infections.