Faecal Calprotectin in Treated and Untreated Children With Coeliac Disease and Juvenile Idiopathic Arthritis.

The present study aimed to provide evidence on whether children at risk of gastrointestinal inflammation have increased measurements of faecal calprotectin (FC). FC was measured in 232 children; 55 children (n = 11 treatment naïve) with juvenile idiopathic arthritis (JIA), 63 with coeliac disease (CD); 17 with new diagnosis before and after treatment on gluten-free diet and 114 controls. None of the treatment-naive children with JIA had raised FC. Four JIA patients on treatment had a raised FC but in all cases a repeat test was normal. In newly diagnosed patients with CD, the median (interquartile range) FC was higher 36.4 (26-61) than that in controls 25.0 (23-41) mg/kg (P = 0.045) but this significantly decreased 25 (25-25) mg/kg (P = 0.012) after 6 months on gluten-free diet. Random measurements of FC are not raised in children with JIA or CD. A significant elevation of FC in these groups is not explained by their diagnosis and therefore needs further investigation.