Inborn errors of immunity (IEI) most commonly present during childhood, including infancy. However, advances in early diagnosis through newborn screening, improved monitoring and management of complications, and progress in therapeutic approaches such as hematopoietic cell transplantation have led to an increasing number of patients surviving into adulthood. As most IEIs require ongoing specialized medical care beyond childhood, and patients may additionally develop common age-related comorbidities in adulthood, it is considered difficult to provide optimal long-term care within pediatric services alone. Therefore, many patients with IEI require transition to adult healthcare services. In Japan, the Transition Working Group of the Japan Pediatric Society (JPS-TWG) published recommendations on transitional care for patients with childhood-onset diseases in 2014. Subsequently, in 2023, the TWG further clarified the definitions of transitional care, transition, and transfer to adult healthcare services.
The Transition Working Group of the Japanese Society for Immunodeficiency and Autoinflammatory Diseases (JSIAD-TWG) conducted questionnaire surveys of JSIAD physician members in 2023 and 2025 regarding their current practices in transition support. This study reports the current status of adult patient care within pediatric settings, the progress of transition, specific transition support initiatives, and changes observed over the two-year period. As no nationwide survey targeting experts has previously been conducted in Japan regarding transitional care and transfer to adult services in IEI, the present findings provide a basis for discussing future perspectives on transitional care required for this rare group of disorders.
