Immune Profiling of Refractory cSLE Exposed to CD3×CD19 BiTE

Other illness

• Inability to obtain peripheral blood samples of adequate quality for immunologic analyses, including insufficient sample volume, severe hemolysis, or failure to meet predefined cell viability criteria.
• Presence of acute severe infection, acute organ decompensation, or other acute medical conditions that may substantially interfere with immune profiling analyses.
• Significant risk associated with blood sampling, such as severe anemia, serious coagulation disorders, or other conditions deemed by the investigator to pose unacceptable risk for phlebotomy.
• Inability to obtain essential clinical data required for immune-clinical correlation analyses (e.g., disease activity scores, complement levels, autoantibody results, or renal parameters).
• Any other condition that, in the opinion of the investigator, may compromise study completion, data integrity, or participant safety.

Other

• Participants meeting any of the following criteria will be excluded:
• Refusal of the legal guardian to allow participation or withdrawal of permission for use of biological samples, or lack of assent from the child when applicable.

• 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.
  • 5.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.
  • 6.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.