Anti-gastric parietal cell antibodies for autoimmune gastritis screening in juvenile autoimmune thyroid disease

Patients with autoimmune thyroid disease (ATD) have a higher prevalence of autoimmune gastritis (AIG) compared with the general population. The association between ATD and AIG is poorly characterized in the pediatric age. We reviewed the prevalence of anti-gastric parietal cell antibodies (PCA) in young patients with ATD to evaluate its usefulness as a marker for AIG screening.

We evaluated 220 children and adolescents (11.28 ± 6.37 years) with ATD (186 with autoimmune thyroiditis (AT) and 34 with Graves' disease (GD). At ATD diagnosis and annually thereafter, blood counts and PCA levels were measured. In patients positive for PCA, plasma gastrin, chromogranin A, vitamin B₁₂, iron and ferritin levels and H. pylori antigen were measured. PCA-positive patients > 18 years were invited to undergo a gastroscopic exam.

PCA positivity was detected in ten (4.5%) subjects (5F/5M; 12.6 ± 3.4 years). The prevalence of PCA positivity was not significantly different in the comparison of GD and AT patients (p = 0.9). PCA positivity was detected after 2.7 ± 2.7 years of follow-up in AT and 4.4 ± 4.0 years in GD (p = 0.4). Autoantibody positivity was more prevalent in female patients, in both AT and GD (p = 0.02 and p = 0.03, respectively). At detection of PCA positivity, five out of ten PCA-positive patients had iron deficiency, four vitamin B₁₂ deficiency, two anemia, three hypergastrinemia and two elevated chromogranin values. Two patients had H. pylori infection. Gastroscopy was performed in the five ATD patients and in all patients, AIG was confirmed.

In the juvenile population, ATD and AIG may also be associated. PCA screening is useful to detect subjects at risk for this condition. Due to the longer life expectancy of the pediatric population and considering the relatively high risk of malignant transformation, early surveillance monitoring is mandatory for children and adolescents with ATD.