Abstract: Objective To analyze the expression level of signaling transduction factor TCR ζ chain gene in T cells from patients with B-cell non-Hodgkin's lymphomas (B-NHL). Methods Real-time RT-PCR with SYBR GreenⅠtechnique was used for detecting the mRNA level of TCR ζ chain gene in peripheral blood mononuclear cells (PBMCs) of 17 patients with B-NHL, and 17 cases healthy adults served as control. The β2-microglobulin gene (β2M) was used as an endogenous reference. Relative mRNA expression level of TCR ζ chain gene was analyzed bythe 2－ △ Ct ×100% method. Results TCR ζ chain gene was expressed in all patients with B-NHL. Compared with healthy control, the relative mRNAlevel of TCR ζ chain gene of patient was significantly decreased ( P =0.000). All samples from healthy individuals expressed normal level of TCR ζ chain gene, which is 3.26 times higher than that from B-NHL patients. There was no significant correlation between the expression level of TCR ζ chain gene and age of patients with B-NHL. Conclusion The low mRNA level of TCR ζ chain gene could be identified in peripheral blood of patients with B-NHL, which might related to cellular immunodeficiency in most of B-NHL patients.