Incidence and implications of anti-rituximab antibodies in nephropathies and other immune-mediated diseases: a narrative review.

Rituximab is a chimeric anti-CD20 monoclonal antibody widely used in immune-mediated and hematologic diseases, but its efficacy may be limited by the development of anti-rituximab antibodies (ADAs). This narrative review summarizes current evidence on the incidence, detection, and clinical implications of ADAs in nephropathies and other immune-mediated disorders. ADA prevalence varies markedly across diseases and is influenced by assay methodology, timing of testing, and patient immune background. Although not all ADAs are clinically relevant, their presence has been associated with lower rituximab levels, earlier B-cell repopulation, reduced clinical/immunological remission, more frequent relapses, and hypersensitivity reactions. Overall, ADAs represent an underrecognized factor that may affect rituximab efficacy and safety, supporting the need for improved monitoring and more personalized therapeutic strategies.