MAPJAG investigates the biological mechanisms driving joint and gut inflammation in children and young people with juvenile idiopathic arthritis (JIA) and inflammatory bowel disease (IBD). By analysing tissue samples from affected patients and healthy controls, the study aims to uncover disease-specific changes, improve understanding of disease progression, and support the development of personalised treatment approaches.
This study does not involve testing any medicinal product or treatment. Instead, it collects and analyses biological samples without altering medical management. All procedures, including joint injections, endoscopies, and anaesthesia, follow standard clinical care. Participants undergoing joint injections or endoscopies for medical reasons may be invited to provide additional samples during their procedures.
MAPJAG builds on pioneering research that has transformed understanding of inflammatory arthritis in adults. Until now, most JIA research has focused on blood or joint fluid due to the challenges of accessing synovial tissue, the site of disease activity. However, these indirect samples do not fully capture disease processes within the joint. We have developed a minimally invasive, well-tolerated ultrasound-guided biopsy technique that allows safe collection of synovial tissue. This method has already revolutionised rheumatoid arthritis (RA) research, leading to new therapy targets and biomarker-driven treatment strategies. MAPJAG extends this approach to children with JIA, offering unprecedented insights into paediatric disease mechanisms.
The study takes a precision pathology approach, linking tissue pathology with disease progression and treatment response. By combining synovial and gastrointestinal tissue analysis with clinical data, MAPJAG helps identify molecular markers that predict disease severity and therapy outcomes. This research is essential for guiding future treatment strategies and improving long-term patient care.
Children and young people with JIA, IBD, and healthy controls are recruited across multiple clinical sites, including Birmingham Women’s and Children’s Hospital NHS Foundation Trust, Great Ormond Street Hospital NHS Foundation Trust, and Newcastle upon Tyne Hospitals NHS Foundation Trust. All procedures take place at the referring sites, while tissue samples are processed at the University of Birmingham, University College London, and Newcastle University.
Patients with JIA undergoing joint injections for clinical care are offered the option of a synovial biopsy at the same time, using the same skin incision. Similarly, patients with IBD undergoing routine endoscopy are invited to provide additional gut biopsies. Healthy controls are identified through clinical care pathways, such as children undergoing knee arthroscopies for non-inflammatory conditions, and provide comparable biological samples. These comparisons are crucial for distinguishing disease-related changes from normal variation
Alongside tissue samples, MAPJAG gathers comprehensive clinical data, including demographics, disease activity, treatment history, and lifestyle factors. Participants also provide optional blood, stool, saliva, and urine samples. This integrated dataset allows for detailed molecular and cellular analysis, helping to uncover mechanisms of disease and identify biomarkers that could predict disease progression or therapy response.
Given the rarity of JIA compared to RA, it is essential to expand research networks and recruit sufficient participants to address key scientific questions. MAPJAG provides a robust multi-centre framework that strengthens future paediatric inflammatory disease research.
MAPJAG aims to recruit 200 participants, including patients with JIA, IBD, and healthy controls. The study continues as an ongoing initiative, with recruitment expanding as additional funding is secured and new research sites join. All eligible children are given the opportunity to participate, ensuring a growing dataset that supports long-term research.
MAPJAG is transforming the landscape of paediatric inflammatory disease research. By applying advanced tissue analysis to minimally invasive biopsies, it bridges a critical knowledge gap in JIA and IBD. This study not only enhances understanding of disease mechanisms but also lays the groundwork for biomarker discovery and personalised treatment strategies. Through its multi-centre collaboration and innovative approach, MAPJAG is driving the future of paediatric rheumatology and gastroenterology research.
