The Feature of TCR Zeta Gene in CD4+ and CD8+ T Cells in Patients with CML.

The T-cell receptor (TCR) zeta chain is a master sensor and regulator of lymphocyte responses which plays a critical role in TCR-mediated signal transduction. The abnormal expression of TCR zeta gene was found in some malignancies and immune disease. Cellular immune deficiency is the common feature in patients with chronic myeloid leukemia (CML). Our previous studies had showed that 60% of CML patients displayed an abnormally low expression of TCR zeta chain in peripheral blood mononuclear cells (PBMCs). To further estimate the changes of zeta chain expression of T-lymphocyte subsets in CML, TCR zeta chain gene expression level in purified CD4+ and CD8+ T cells sorted by MACS were detected by real-Time PCR with SYBR Green I technique, CD4+ and CD8+ T cells from both 10 cases with CML and 10 normal individuals were selected to analyze in the study. β2 -microglobulin was used as an endogenous reference. Relative changes in TCR zeta gene expression level were used by the 2^−ΔCt×100% method. The relative mRNA expression level of TCR zeta gene in CD4+ and CD8+ T cells from CML was 4.06±4.82% and 3.82±4.25% respectively, whereas 7.75±2.52% and 5.19±1.25% were found in normal individuals. There was a wide range in the TCR zeta gene expression level of CD4+ T cells from CML patients (0.23–15.93%,) with a median value of 1.77%, whereas the a range of (4.74–12.81%) with a median of 7.93% was showed in normal controls (P=0.046). The expression level of TCR zeta gene in CD8⁺ T cells from controls ranged from 3.47% to 6.75% (median 5.52%) and in CML patients from 0.86% to 15.55% with a median of 2.51% (P=0.340). The results indicated that, compared with normal controls, zeta chain gene expression was obviously down-regulated in CD4+ T cells from patients with CML. However, there was not significant different in expression level of TCR zeta gene of CD8+ T cells between CML patients and normal individuals. Moreover, the expression level of TCR zeta gene is nonsignificant age-associated or gender-link in CD4+ T cells and CD8+ T cells from patients with CML. In conclusions, the results provide at first the difference of TCR-zeta gene expression pattern in CD4+ and CD8+ T cells from patients with CML, this may be reflective of signaling difference between the different T cell subtypes in immunodeficiency state of patients.