Batch-to-Batch Variation and Patient Heterogeneity in Thymoglobulin Binding and Specificity: One Size Does Not Fit...

Area of Science:

• Immunology
• Transplantation Science
• Endocrinology

Background:

• Thymoglobulin, used for allograft rejection prevention, is investigated for type 1 diabetes immunotherapy.
• It comprises rabbit antibodies targeting human thymocytes and leukocytes, with potential batch-to-batch variations due to its production method.

Purpose of the Study:

• To compare different Thymoglobulin batches for antibody composition and inter-individual variations in binding to peripheral blood mononuclear cells (PBMCs) and T cell subsets.
• To assess Thymoglobulin-induced cytokine production and its variability.

Main Methods:

• Four Thymoglobulin batches were conjugated and used to stain PBMCs from healthy donors.
• Flow cytometry analyzed binding to PBMC and T cell subsets.
• Cytokine induction was measured in whole blood incubated with Thymoglobulin.

Main Results:

• Thymoglobulin bound to all PBMC subpopulations, including regulatory T cells.
• Binding showed high inter-individual variability and moderate batch-to-batch differences.
• Cytokine release syndrome-related cytokines increased variably across donors and batches.

Conclusions:

• Inter-individual variability in Thymoglobulin binding and cytokine response may explain differing clinical outcomes.
• Personalized dose adjustments are suggested to optimize efficacy and minimize adverse effects of Thymoglobulin therapy.