Coexistence of two functioning T-cell repertoires in healthy Ex- thalassemics bearing a persistent mixed chimerism years after bone marrow transplantation

Manuela Battaglia, Marco Andreani, Marisa Manna, Sonia Nesci, Paola Tonucci, Barbara Persini, Gioacchino Robustelli Della Cuna, Arcangelo Nocera, Jack Gorski, Guido Lucarelli, Raffaele De Palma

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Abstract

Bone marrow transplantation (BMT) from an HLA-identical donor is an established therapy to cure homozygous β-thalassemia. Approximately 10% of thalassemic patients developed a persistent mixed chimerism (PMC) after BMT characterized by stable coexistence of host and donor cells in all hematopoietic compartments. Interestingly, in the erythrocytic lineage, close to normal levels of hemoglobin can be observed in the absence of complete donor engraftment. In the lymphocytic lineage, the striking feature is the coexistence of immune cells. This implies a state of tolerance or anergy, raising the issue of immunocompetence of the host. To understand the state of the T cells in PMC, repertoire analysis and functional studies were performed on cells from 3 ex-thalassemics. Repertoire analysis showed a profound skewing. This was due to an expansion of some T cells and not to a collapse of the repertoire, because phytohemagglutinin stimulation showed the presence of a complex repertoire. The immunocompetence of the chimeric immune systems was further established by showing responses to alloantigens and recall antigens in vitro. Both host and donor lymphocytes were observed in the cultures. These data suggest that the expanded T cells play a role in specific tolerance while allowing a normal immune status in these patients.

Original languageEnglish
Pages (from-to)3432-3438
Number of pages7
JournalBlood
Volume94
Issue number10
Publication statusPublished - Nov 15 1999

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ASJC Scopus subject areas

  • Hematology

Cite this

Battaglia, M., Andreani, M., Manna, M., Nesci, S., Tonucci, P., Persini, B., Robustelli Della Cuna, G., Nocera, A., Gorski, J., Lucarelli, G., & De Palma, R. (1999). Coexistence of two functioning T-cell repertoires in healthy Ex- thalassemics bearing a persistent mixed chimerism years after bone marrow transplantation. Blood, 94(10), 3432-3438.