Pediatric Rheumatic Disorders Revisited: Integrating Imaging and Pathophysiologic Insights across the...

Recent advances in immunologic and molecular research on rheumatic diseases have significantly improved understanding of the diverse group of immune-mediated disorders. Rheumatic diseases were traditionally considered autoimmune diseases, caused by impaired adaptive immunity and often associated with pathogenic autoantibodies. However, in the late 20th century, certain genetic rheumatic diseases-such as tumor necrosis factor receptor-associated periodic syndrome (TRAPS) and familial Mediterranean fever (FMF)-were found to result from antigen-independent activation of innate immune cells and the subsequent cytokine-mediated inflammation. This discovery introduced the new concept of autoinflammatory diseases, characterized by dysregulation of innate immunity. Although autoimmune and autoinflammatory diseases were initially regarded as distinct categories, substantial overlap has become evident. For instance, autoantibodies can be detected in disorders primarily affecting innate immunity, while recent cytokine-targeting therapies have proven effective for classic autoimmune diseases, such as systemic lupus erythematosus (SLE) and dermatomyositis. These insights led to the concept of an autoinflammatory-autoimmune continuum, highlighting that dysregulation of the interaction between innate and adaptive immune systems contributes to the clinical symptoms of rheumatic diseases. The authors explore clinical, imaging, pathophysiologic, and therapeutic aspects of pediatric rheumatic diseases through the lens of this continuum, providing a comprehensive overview of current diagnostic and treatment strategies. ^© RSNA, 2026 Supplemental material is available for this article.