Quantitative assessment of T cell repertoire recovery after hematopoietic stem cell transplantation

Abstract

A limited T cell receptor (TCR) repertoire after allogeneic hematopoietic stem cell transplantation can be associated with poor clinical outcomes and greater susceptibility to infections. Jeroen van Heijst and colleagues have combined 5′ RACE PCR with deep sequencing technology to provide a reproducible and quantitative measure of the recovery of TCR diversity during the first year of transplantation with three commonly used stem cell sources in patients with various hematologic malignancies. Delayed T cell recovery and restricted T cell receptor (TCR) diversity after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are associated with increased risks of infection and cancer relapse. Technical challenges have limited faithful measurement of TCR diversity after allo-HSCT. Here we combined 5′ rapid amplification of complementary DNA ends PCR with deep sequencing to quantify TCR diversity in 28 recipients of allo-HSCT using a single oligonucleotide pair. Analysis of duplicate blood samples confirmed that we accurately determined the frequency of individual TCRs. After 6 months, cord blood–graft recipients approximated the TCR diversity of healthy individuals, whereas recipients of T cell–depleted peripheral-blood stem cell grafts had 28-fold and 14-fold lower CD4+ and CD8+ T cell diversities, respectively. After 12 months, these deficiencies had improved for the CD4+ but not the CD8+ T cell compartment. Overall, this method provides unprecedented views of T cell repertoire recovery after allo-HSCT and may identify patients at high risk of infection or relapse.