T Cell Receptor Excision Circles (TRECs) Decrease in Patients after Allogeneic Stem Cell Transplantation.

Human thymus is required for establishment of a T-cell pool in fetal life, T-cell emigration from thymus (thymic recent emigrants [TRECs]) is a continuous thymic-dependent process. To analyze the content of signal joint Tcell receptor excision DNA circles signal joint T cell receptor excision DNA circles(sjTRECs) within peripheral blood mononuclear cells (PBMCs), thereby to infer the level of naive T cells and the recent thymic output function in patients with allogeneic stem cell transplantation. We used real-time polymerase chain reaction (PCR) to quantify SjTRECs in 5 patients with chronic myeloid leukemia-chronic phase. Five patients(4 males, 1 females; median age 37 years,) who underwent HLA-matching sibling BMT and/or peripheral blood stem cell transplantation (PBSCT) at our department. Quantitative detection of sjTRECs in DNA of peripheral blood mononuclear cells from 13 normal individuals. The median value of sjTRECs copies P1 000 PBMCs was 4.37±3.64 in normal individuals whereas it was 0.57±0.51 copies P1 000 PBMCs in patients at least two years after allogeneic stem cell transplantation (P < 0. 03). We conclude that these Patients decrease in recent thymic output function,. Therefore, measurement of sjTREC may provide an important tool for predicting thymus-dependent T-cell reconstitution after transplantation.