Varying frequencies of T cells exhibiting CMV peptide-specific reactivity to allo-MHC are present in cord blood transplant units (P2228)

Abstract

Abstract Cord blood transplants are a desirable treatment option for a number of hematopoietic diseases due partly to the increased tolerance of HLA mismatches between transplant donor and recipient, manifest in the decreased occurrence of GVHD. Unfortunately, these patients also have an increased risk of reactivating latent infections (e.g. CMV) post-transplant which will ultimately be fatal; likely due to the same decreased T cell functioning that results in HLA mismatch tolerance. Viral reactivation is by no means universal after transplant, however, and while certain factors are known to increase a patient’s risk (e.g. GVHD or in-vivo t cell depletion), there remains no good method for predicting susceptibility. Using MHC tetramers, our lab has found a population of T cells specific to the HLA-A2 CMV peptide in not only A2, but also non-A2 cord blood samples. The frequency of these cells varies widely between cord blood units, which could be a potential signifier of a unit’s efficacy in fighting viral reactivation. Further, preliminary studies suggest that these cells have a specificity and functionality that would make them therapeutically useful.