False-positive tissue transglutaminase antibody levels occur in HIV-positive patients: HLA typing is essential

Clinical settings in which human leukocyte antigen typing is still useful in the diagnosis of celiac disease

Celiac disease (CD) is a systemic autoimmune disorder triggered by gluten ingestion ingenetically predisposed individuals. It is characterized by intestinal histological damage and the production of specific autoantibodies. The latest European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) 2020 guidelines have excluded human leukocyte antigen (HLA) genotyping from the no-biopsy diagnostic approach due to its weak positive predictive value, limited availability, and high cost in some countries. However, HLA genetic testing remains valuable in certain clinical contexts. This study provided practical indications for when to request and how to interpret HLA genotyping, emphasizing its continued relevance for CD diagnosis in specific cases. We also proposed a strategy for monitoring the risk of developing type 1 diabetes (T1D) in patients with CD, based on the risk stratification carried by different HLA genotypes. A retrospective analysis of 746 patients with CD and 627 controls was conducted at our hospital starting in 2012, when HLA genotyping became mandatory for the diagnosis of CD. We identified key clinical scenarios where HLA testing remains useful. Several high risk HLA-DQ genotypes strongly associated with CD were highlighted, including HLA-DQ2.5/HLA-DQ2.2 and HLA-DQ2.5/HLA-DQ2.5. Notably, while the HLA-DQ2.5/HLA-DQ2.2 genotype is linked to CD, it appears to confer protection against T1D. To support clinical practice, we presented a table clarifying commonly used HLA terminology, and another summarized the main clinical situations in which HLA genotyping should still be considered. These findings underscore the dual role of HLA testing: Not only can it help rule out CD in selected cases, but it also identifies patients with CD at risk for T1D, guiding personalized monitoring strategies.

Gastrointestinal Diseases in Children Living with HIV

Thanks to the advances in antiretroviral therapies (ART) and early diagnosis, pediatric HIV has turned into a chronic infection that requires the collaboration of all pediatric subspecialists for holistic patient management. Gastrointestinal complaints are a frequent reason for seeking access to medical care in all pediatric patients worldwide. Intestinal involvement is present in virtually all children with HIV infections. In high-prevalence settings, up to 25% of children accessing the hospital for diarrhea are diagnosed with HIV. More than half of patients with advanced disease present with gastrointestinal symptoms, from mild infectious diarrhea to severe gastrointestinal impairment, malabsorption and failure to thrive. Gastrointestinal disorders do not spare children on ART, particularly in the initial months of therapy. ART-associated pancreatitis and hepatitis are rare but potentially severe adverse events, whereas lower abdominal symptoms have been reported in more than a third of patients. The latter are usually mild and transient, but may limit ART adherence; a correct framing of the problem is necessary to minimize therapy switches while optimizing the quality of life of children on ART. This review aims to provide state-of-the-art guidance for the initial approach to gastrointestinal diseases in children living with HIV.