Autoimmune gastritis in children: A prospective cohort with serologic screening in at‐risk patients

OBJECTIVES: Autoimmune gastritis (AIG) is a chronic immune-mediated condition characterized by the destruction of the gastric oxyntic mucosa. Though commonly diagnosed in adults, its occurrence in pediatric patients with autoimmune comorbidities is increasingly reported. This study aims to determine the prevalence of AIG in children with Type 1 diabetes, autoimmune thyroiditis, primary immune regulatory disorders, or refractory anemia (RA), and to assess the diagnostic performance of anti-parietal cell antibodies (APCAs) and anti-intrinsic factor antibodies (AIFAs) in this group of patients. METHODS: We conducted a prospective study in 203 children aged 4-17 years. All underwent laboratory screening for APCAs and AIFAs. Those who tested positive for at least one of the two antibodies were referred for upper endoscopy with gastric biopsies for histological confirmation. A control group of 26 patients with dyspeptic symptoms and negative histology was also evaluated. RESULTS: Nineteen patients tested positive for APCAs and/or AIFAs (9.4%). Among them, nine (47.4%) had histologically confirmed AIG. Additionally, two patients with RA and negative serology were diagnosed with AIG based on histology. Thus, a total of 11 patients (5.4%) were diagnosed with AIG. The sensitivity and specificity of antibody testing for AIG were 81.8% and 77.9%, respectively. CONCLUSIONS: AIG may be underdiagnosed in children with autoimmune conditions. Our findings support the integration of serological screening with histological assessment to enhance early recognition. The combined use of APCAs and AIFAs demonstrates good diagnostic accuracy, offering a valuable tool for timely diagnosis and improved management in this at-risk pediatric population.