A Prospective Observational Study of Immune Profiling in Childhood-Onset Systemic Lupus Erythematosus Under CD3×CD19 Bispecific T-Cell Engager Exposure
This prospective observational study aims to characterize the peripheral immune landscape of pediatric patients with childhood-onset systemic lupus erythematosus ( cSLE) who are receiving CD3×CD19 bispecific T-cell engager (BiTE) therapy under a separate, approved exploratory clinical study. The present study does not assign, modify, or influence any therapeutic interventions. Peripheral blood samples are collected longitudinally at predefined time points in parallel with routine clinical follow-up. Immune profiling is performed using multiparameter flow cytometry, with single-cell sequencing conducted in a subset of samples to further explore cellular and molecular features. Clinical data, including disease activity indices and relevant serological biomarkers, are recorded concurrently. The objective of this study is to describe immune cell dynamics and immune features associated with changes in disease activity in cSLE, and to explore potential biomarker candidates that may inform future immune-monitoring strategies and mechanistic research in this population.
• Participants must meet all of the following criteria:
‣ Age ≥ 5 years.
⁃ Diagnosis of systemic lupus erythematosus (SLE) confirmed according to the 2019 EULAR/ACR classification criteria.
⁃ Refractory or persistently active SLE, defined by clinical evaluation and meeting at least one of the following conditions:
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‣ Inadequate response to prior standard treatments, including oral glucocorticoids, antimalarial agents, conventional immunosuppressants (cyclophosphamide, mycophenolate mofetil, azathioprine, methotrexate, cyclosporine, tacrolimus, sirolimus, leflunomide), and biologic therapies (telitacicept, belimumab, rituximab).
⁃ Moderate to high disease activity, such as a SLEDAI score ≥ 6. 4.Receiving CD3×CD19 bispecific T-cell engager (BiTE) therapy as part of routine clinical management, with traceable dosing information and treatment timeline.
⁃ Availability of peripheral blood samples collected before and/or after CD3×CD19 BiTE exposure, obtained during routine clinical assessment or prospective follow-up, that are suitable for immunologic analyses.
⁃ Prior informed consent obtained in a related clinical study or clinical care context that explicitly permits the storage and secondary use of biological samples and associated clinical data for disease-related scientific research, including prospective analyses during subsequent follow-up; and willingness of the child to cooperate with study follow-up procedures, as appropriate.