title: Optimizing a photoallodepletion protocol for adoptive immunotherapy after haploidentical SCT.
abstract: In adults, one-haplotype-mismatched haematopoietic SCT (haploidentical HSCT) is associated with slow immune recovery due to decaying thymic function and extensive T-cell depletion of the graft. Although essential for preventing GVHD, T-cell depletion underlies the major reasons for transplant failure: leukemia relapse and infections, with infection-related mortality accounting for about 40% of non-leukemic deaths. Adoptive T-cell therapy would be helpful for these patients but to administer it without causing GVHD, alloreactive T cells need to be eliminated from donor T lymphocytes before infusion. In a preclinical study, to address this problem, we determined the efficacy of photodynamic purging of alloreactive T cells, by investigating combinations of parameters in order to achieve maximum allodepletion, preservation of T-regulatory cells and of pathogen and leukemia-specific T-cell responses in donor-vs-recipient MLR. We also needed to identify an optimal method to quantify the Ag-specific T-cell repertoires. Optimal procedures were identified. In particular, we compared limiting-dilution analyses (LDA) of proliferating T cells with H(3)-thymidine incorporation by bulk T cells and with flow cytometry CD25 expression, which is accepted as a T-cell activation marker. This study demonstrated that LDA is a reliable, predictable and sensitive method for measuring alloreactive, pathogen- and leukemia-specific T-cell frequencies.
authors.affiliation: Division of Hematology and Clinical Immunology, Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy. perruccio@unipg.it
authors.forename: K
authors.initials: K
authors.lastname: Perruccio
authors.forename: F
authors.initials: F
authors.lastname: Topini
authors.forename: A
authors.initials: A
authors.lastname: Tosti
authors.forename: A
authors.initials: A
authors.lastname: Carotti
authors.forename: E
authors.initials: E
authors.lastname: Burchielli
authors.forename: L
authors.initials: L
authors.lastname: Ruggeri
authors.forename: A
authors.initials: A
authors.lastname: Mancusi
authors.forename: E
authors.initials: E
authors.lastname: Urbani
authors.forename: F
authors.initials: F
authors.lastname: Aversa
authors.forename: M F
authors.initials: MF
authors.lastname: Martelli
authors.forename: A
authors.initials: A
authors.lastname: Velardi
mesh_terms: D015331:Cohort Studies; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D006239:Haplotypes / Q000276:immunology; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D016219:Immunotherapy, Adoptive / Q000379:methods*; D008213:Lymphocyte Activation / Q000276:immunology*; D008212:Lymphocyte Depletion / Q000379:methods*; D010778:Photochemotherapy / Q000379:methods; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D018984:Epitopes, T-Lymphocyte