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Published on: March 14, 2011
Optimizing a photoallodepletion protocol for adoptive immunotherapy after haploidentical SCT
K Perruccio1, F Topini, A Tosti
1Division of Hematology and Clinical Immunology, Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy. perruccio@unipg.it
Bone Marrow Transplantation
|December 6, 2011
Summary
Photodynamic purging effectively eliminates alloreactive T cells, crucial for preventing graft-versus-host disease (GVHD) after haploidentical hematopoietic stem cell transplantation (HSCT). Limiting-dilution analysis (LDA) reliably quantifies these specific T cells.
Area of Science:
- Immunology
- Transplantation immunology
- Cellular therapy
Background:
- Haploidentical hematopoietic stem cell transplantation (HSCT) in adults faces challenges with slow immune recovery and high rates of leukemia relapse and infections.
- T-cell depletion, while preventing graft-versus-host disease (GVHD), contributes to transplant failure by increasing susceptibility to infections and relapse.
- Adoptive T-cell therapy is a potential strategy, but requires elimination of alloreactive T cells to avoid GVHD.
Purpose of the Study:
- To evaluate the efficacy of photodynamic purging for eliminating alloreactive T cells from donor lymphocyte infusions.
- To optimize photodynamic purging parameters for maximum allodepletion while preserving regulatory T cells and pathogen/leukemia-specific T-cell responses.
- To identify a reliable method for quantifying antigen-specific T-cell repertoires.
Main Methods:
- Preclinical study involving donor-vs-recipient mixed lymphocyte reactions (MLR).
- Investigation of photodynamic purging parameters for T-cell depletion.
- Comparison of limiting-dilution analysis (LDA), [3H]-thymidine incorporation, and flow cytometry for quantifying antigen-specific T-cell frequencies.
Main Results:
- Optimal photodynamic purging procedures were identified, achieving significant allodepletion.
- Limiting-dilution analysis (LDA) demonstrated superior reliability, predictability, and sensitivity in measuring alloreactive, pathogen-, and leukemia-specific T-cell frequencies compared to other methods.
- Preservation of T-regulatory cells and pathogen/leukemia-specific T-cell responses was assessed.
Conclusions:
- Photodynamic purging is a viable strategy for eliminating alloreactive T cells in the context of haploidentical HSCT.
- Limiting-dilution analysis (LDA) is a robust and sensitive method for quantifying antigen-specific T-cell responses, essential for assessing the efficacy of T-cell purging and therapy.
