Immune reconstitution after hematopoietic stem cell transplantation (HSCT) with a conditioning regimen has appeared to be a promising treatment for autoimmune diseases and hematologic malignancies. This study aimed to assess the T cell receptor (TCR) repertoire diversity in CD4+ cells of patients with hematological malignancies who received allogeneic or autologous HSCT. The diversity of the TCR repertoire was evaluated in 13 patients with hematologic malignancies before and four months after HSCT. Amino acid changes in the 25 Vβ families were evaluated using Spectratyping and data were presented as Hamming distance (HD). HD more than 20% was considered a change in TCR repertoire after HSCT. The mean HD was significantly changed after transplantation in all Vβ gene families, with most amino acid changes in p4 and p22 families. There was a strong negative correlation between the HD as the index of TCR repertoire and age (r = -0.62,). The results revealed no association between HD mean and parameters such as sex, disease, conditioning regimen, and type of transplantation. Our data revealed that commonly used conditioning regimens in Iran could successfully cause TCR repertoire diversity in patients with hematologic malignancies in the short term. The amount of change in TCR repertoire was inversely correlated with the increasing age of patients.
Keywords: Hamming distance; Hematopoietic stem cell transplantation; Spectratyping; T cell receptor.