Subclinical Gastrointestinal Involvement in Juvenile Systemic Lupus Erythematosus

This cross-sectional case-control study aims to evaluate fecal calprotectin levels and intestinal ultrasound findings for the detection of subclinical gastrointestinal involvement in children with juvenile systemic lupus erythematosus compared with healthy controls.

Inclusion Criteria: * Children less than 18 years of age * Diagnosis of juvenile systemic lupus erythematosus according to SLICC criteria * Disease duration of at least 3 months * Age- and sex-matched healthy controls * Written informed consent from parents or legal guardians Exclusion Criteria: * \- Established diagnosis of inflammatory bowel disease or other primary gastrointestinal disorder * Significant gastrointestinal manifestations (persistent abdominal pain, diarrhea, vomiting, GI bleeding, significant unexplained weight loss) * Active gastrointestinal infection within the preceding 4 weeks * Antibiotics, probiotics, or NSAIDs within the 2 weeks preceding stool sample collection * Other autoinflammatory or overlapping autoimmune diseases * Chronic liver or renal disease unrelated to JSLE