Clinical considerations for immune dysregulation and immunodeficiency in Down syndrome

Down syndrome (DS), the genetic condition caused by trisomy 21 (T21), is characterized by lifelong immune dysregulation leading to high rates of autoimmune disorders, elevated risk of complications from infections, immune hypersensitivity, and a unique form of immunodeficiency. It is now appreciated that DS shares key hallmarks with interferonopathies, with vast remodeling of all branches of the immune system, hypercytokinemia, and widespread autoantibody production. Here within, we review the existing literature with an emphasis on clinical considerations toward monitoring, management, and therapeutic opportunities. We highlight recent research advances that illuminate diagnostic approaches to evaluate immune dysregulation in DS. We also discuss the evidence supporting specific immunomodulatory strategies that could have multidimensional benefits in this population, including JAK inhibitors, intravenous immunoglobulin, and B cell–depleting agents.