Combinations of inhibitory receptors are expressed on CD8+ T cells in pediatric subjects following bone marrow or umbilical cord blood transplantation. (P2162)

• Published in: The Journal of immunology (1950) Vol. 190; no. 1_Supplement; pp. 69 - 69.19
• Main Authors: Soudeyns, Hugo, Gravel, Catherine, Caty, Martine, Mezziani, Samira, Le Campion, Armelle, Duval, Michel, Salem Fourati, Insaf
• Format: Journal Article
• Language: English
• Published: 01.05.2013
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.190.Supp.69.19

Abstract Umbilical cord blood transplantation (UCBT) is commonly used to treat a variety of hematologic or neoplastic disorders in children. Compared to bone marrow transplantation (BMT), UCBT is associated with slow engraftment and a higher incidence of graft failure and opportunistic infections. The aim of the present study was to identify immunologic biomarkers expressed by CD8+ T cells during the post-transplant period that predispose patients to develop complications following UCBT or BMT. Pediatric patients who underwent UCBT (n=16) or BMT (n=7) were enrolled at CHU Sainte-Justine. Samples were obtained from graft inoculums and from transplanted subjects during 24 months of follow-up. Expression of inhibitory receptors associated with CD8+ T cell exhaustion (PD-1, CTLA-4, 2B4, TIM-3, BTLA-4, LAG-3) was studied ex vivo using multiparameter flow cytometry. Results showed that inhibitory receptors were expressed at very low levels in UCB graft inoculums. However, in the first 100 days after UCBT or BMT, a notable increase in the frequency PD-1+ CD8+ T cells and 2B4+ CD8+ T cells was observed, and frequencies of PD-1+ and 2B4+ T cells were inversely correlated with absolute CD8+ T cell counts. A low number of CD8+ T cells also co-expressed two or more inhibitory receptors. These results suggest that expression of exhaustion markers by CD8+ T cells in graft recipients during the early post-transplant period may modulate their activity and lead to functional impairment.