In Vitro Evaluation of Graft-versus-Graft Alloreactivity as a Tool to Identify the Predominant Cord Blood Unit before Double Cord Blood Transplantation

Antonia Moretta, Gabriella Andriolo, Daniela Lisini, Miryam Martinetti, Annamaria Pasi, Paolo Rebulla, Davide Soligo, Rosaria Giordano, Lorenza Lazzari, Rita Maccario

Research output: Contribution to journalArticlepeer-review


The transplantation of two cord blood (CB) units obtained from unrelated donors (double CBT) is an effective strategy for adult patients with hematologic malignancies. Sustained hematopoiesis after double CBT is usually derived from a single donor, and only a few transplantation recipients displaying a stable mixed donor-donor chimerism have been reported. We investigated the mechanisms underlying single-donor predominance in double CBT by studying in vitro the role of the graft-versus-graft cell-mediated immune effect in two-way mixed-lymphocyte culture, along with the contribution of differential hematopoietic progenitor (HP) potency in HP mixed cultures. Results for the two-way mixed-lymphocyte culture showed that despite the weak and variable alloantigen-specific cytotoxic potential displayed by CB mononuclear cells, an immune-mediated dominance for one of the two CB units was detected in the majority of experiments. Alloantigen-induced cytotoxic activity was directed toward both CB-HP and phytohemagglutinin (PHA)-activated T lymphoblastoid cells. The CB unit with the higher fold expansion of CD34+ cells in single-expansion culture was prevalent in the HP mixed-expansion culture, as shown by DNA chimerism evaluation. Based on these data, we hypothesize that the dominant CB unit is able to develop prevalent cytotoxic activity toward activated lymphocytes of the other CB unit, thereby preventing them from exerting alloantigen-specific cytotoxic potential against both activated lymphocytes and HPs of the dominant unit. In accordance with this hypothesis, we propose the evaluation of alloantigen-induced cytotoxic activity generated in two-way mixed-lymphocyte culture and directed toward PHA-activated T lymphoblastoid cells as a tool to identify the potentially predominant CB unit before double CBT.

Original languageEnglish
Pages (from-to)1108-1118
Number of pages11
JournalBiology of Blood and Marrow Transplantation
Issue number7
Publication statusPublished - Jul 2012


  • Cytotoxic lymphocyte
  • Hematopoietic progenitor
  • Mixed-lymphocyte reaction

ASJC Scopus subject areas

  • Transplantation
  • Hematology


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