Background: Infections pose a significant challenge for children after solid organ transplantation and are one of the leading causes of morbidity and mortality. Most viral pathogens establish themselves within the first six months post-transplant. With the increased use of various immunosuppressive regimens in pediatric patients, a re-evaluation is necessary to determine optimal treatment protocols. 
Methods: A retrospective analysis was conducted, including so far 116 pediatric patients who underwent kidney or liver transplantation between 2017 and 2024. All patients were under 18 years old at the time of transplantation and were followed for at least six months. Clinical data were obtained from the DZIF registry, a central database collecting information from multiple university hospitals (University Hospital Tübingen, Hannover Medical School, and University Hospital Heidelberg). The study analyzed infection rates, immunosuppressive therapy, complications, and transplantation outcomes while investigating differences based on gender, clinic, and immunosuppressive regimens. In addition, the study will include lung transplants in the future to analyze further differences between the organ systems.
Thematic and Scientific Integration: This study aligns with the MHH focus areas in infection and immunology, transplantation, and regenerative medicine. The research contributes to the understanding of infection-related challenges in pediatric transplantation and aims to optimize immunosuppressive strategies. The study is integrated into the DZIF network and has potential connections with broader national and international transplantation and infection research initiatives. 
Summary of Scientific Results and Outlook: Results indicate that infections are more frequent in liver transplant recipients (4.2 infections per patient) compared to kidney transplant recipients (2.8 infections per patient). Bacterial infections, primarily caused by E. coli and Klebsiella, accounted for 78% of documented cases. Hospitalization due to infections occurred in approximately 40% of patients. Tacrolimus was the primary immunosuppressant in both groups, with additional use of Mycophenolate Mofetil (92%) and steroids (85%). Younger patients (under five years) exhibited a higher incidence of viral infections. Differences between transplantation centers highlighted variations in immunosuppressive management, particularly in the use of Tacrolimus and Basiliximab. 
Future research should focus on optimizing infection prophylaxis and tailoring immunosuppressive strategies to improve long-term transplant outcomes and patient quality of life.