Objective Assess the frequency of anti-H+ /K+ adenosine triphosphatase (ATPase) autoantibodies (AAB) and symptoms of autoimmune gastritis in children and adolescents with type 1 diabetes (T1D). Research design and methods Anti-H+ /K+ ATPase AAB were measured in 402 children and adolescents (210 boys and 192 girls, 11.1 ± 4.5 years) treated for T1D (screened positive for β-cell AAB), along with search of symptoms of anemia (hemoglobin, serum iron, and ferritin levels) and gastric pain. The AAB specific for thyroperoxydase, thyroglobulin, and transglutaminase were also measured. Results Anti-H+ /K+ ATPase AAB were present in 6.5% of children. Their frequency increased with age: 4% at 10 years, 10% at 15 years, and 20% at 20 years. Iron deficiency (45% vs 3.8%), iron deficiency anemia (36% vs 3.8%), antithyroid AAB (24% vs 9.7%), and family history of Graves' disease (25% vs 5.6%) were more frequent in patients with anti-H+ /K+ ATPase AAB. Two patients, a 13-year-old girl and a 11-year-old boy, experienced symptoms (iron deficiency anemia and epigastric pain) which led to diagnosis of autoimmune gastritis confirmed upon fibroscopy. Both showed high levels of anti-H+ /K+ ATPase AAB and atrophic gastritis. Conclusions Autoimmune gastritis presents an age-dependent frequency in children and adolescents with T1D but is rarely symptomatic. Screening for anti-H+ /K+ ATPase AAB should thus target patients with iron deficiency, anemia, epigastralgia, autoimmune thyroiditis, or age over 15 years.
